Battery pack

ABSTRACT

A battery pack including a plurality of battery cells; a plurality of bus bars, each bus bar electrically connecting two different battery cells among the plurality of battery cells, and including coupling pieces at opposite ends thereof that are coupled to the two different battery cells, and a protruding connecting piece at a center of the bus bar that connects the coupling pieces at the opposite ends; and a circuit board on the plurality of bus bars and electrically connected to at least a portion of the plurality of battery cells, the circuit board having escape holes that expose the protruding connection piece of each bus bar.

CROSS-REFERENCE TO RELATED APPLICATION

Korean Patent Application No. 10-2019-0157466, filed on Nov. 29, 2019,in the Korean Intellectual Property Office, and entitled: “BatteryPack,” is incorporated by reference herein in its entirety.

BACKGROUND 1. Field

Embodiments relate to a battery pack.

2. Description of the Related Art

Secondary batteries are rechargeable unlike non-rechargeable primarybatteries. Secondary batteries are used as energy sources of devicessuch as mobile devices, electric vehicles, hybrid electric vehicles,electric bicycles, and uninterruptible power supplies, and according tothe types of external devices using secondary batteries, secondarybatteries may be used as single battery cells or battery packs in whicha plurality of battery cells are connected into a unit.

Small mobile devices such as mobile phones may operate for apredetermined time by using an output and a capacity of a singlebattery, in the case of electric automobiles or hybrid automobiles whichmay have large power consumption, a long driving time, and high-powerdriving, battery packs may be used to meet the power and capacityrequirements, and an output voltage or an output current of a batterypack may increase as the number of battery cells embedded thereinincreases.

SUMMARY

The embodiments may be realized by providing a battery pack including aplurality of battery cells; a plurality of bus bars, each bus barelectrically connecting two different battery cells among the pluralityof battery cells, and including coupling pieces at opposite ends thereofthat are coupled to the two different battery cells, and a protrudingconnecting piece at a center of the bus bar that connects the couplingpieces at opposite ends; and a circuit board on the plurality of busbars and electrically connected to at least a portion of the pluralityof battery cells, the circuit board having escape holes that expose theprotruding connection piece of each bus bar.

Each escape hole may completely expose an entirety of a correspondingprotruding connection piece.

The protruding connection pieces may not overlap a solid portion of thecircuit board that surrounds the escape holes.

Each escape hole may completely accommodate an entirety of acorresponding protruding connection piece.

The circuit board may have a lower side facing the plurality of batterycells and an upper side that is opposite to the plurality of batterycells, along a height direction of the plurality of battery cells, and aplane of each protruding connection piece may be between a plane of theupper side of the circuit board and a plane of the lower side of thecircuit board.

The battery pack may further include a cell holder, the cell holderhaving a first side in which the battery cells are accommodated, and asecond side including hollow protrusions connected to cooling flow pathsbetween adjacent battery cells of the plurality of battery cells.

The bus bars and the circuit board may be on the second side of the cellholder.

Each bus bar may extend between a corresponding pair of the hollowprotrusions that face each other.

The pair of the hollow protrusions may face each other in a directionintersecting a lengthwise extending direction of the bus bartherebetween.

The protruding connection piece of each bus bar may be between thecorresponding pair of the hollow protrusions.

The cell holder may further include pairs of locking steps, into whichthe protruding connection piece of each bus bar is inserted, at each ofthe pairs of hollow protrusions, the pairs of locking steps eachprotruding from wall bodies of the corresponding pair of hollowprotrusions toward the protruding connection piece therebetween.

The cell holder may further include mold holes from which the pairs ofhollow protrusions protrude, at positions corresponding to the pairs oflocking steps, to pass through the cell holder.

Each bus bar may further include position alignment holes for positionalignment with the cell holder, the position alignment holes being inthe protruding connection piece of each bus bar, and the cell holder mayfurther include position alignment pins that are insertable into theposition alignment holes of corresponding bus bars, the positionalignment pins being between the pairs of hollow protrusions.

Pairs of the position alignment pins may be arranged along a lengthwisedirection of a corresponding one of the plurality of bus bars.

The circuit board may further include a bus opening region continuouswith the escape holes in a single hole shape, the bus opening regionexposing the hollow protrusions of the cell holder and the protrudingconnection pieces of the plurality of bus bars.

The bus opening region may expose pairs of the hollow protrusionstogether with the protruding connection pieces therebetween.

The battery pack may further include connection members on the circuitboard, passing through the circuit board, and connected to the batterycells, wherein the circuit board further includes connection openingregions, the connection members pass through the connection openingregions of the circuit board, and the connection opening regions exposepairs of the hollow protrusions facing each other with correspondingconnection members therebetween.

Respective ends of the connection members may be ultrasonically weldedto the circuit board and the battery cell.

The bus opening region and the connection opening region may becontinuous with each other to form a second opening region in a singlehole shape.

The second opening region may expose a first hollow protrusion of thehollow protrusions that is between a first bus bar of the plurality ofbus bars and a first connection member of the connection members, asecond hollow protrusion of the hollow protrusions that faces the firsthollow protrusion with the first bus bar therebetween, and a thirdhollow protrusion of the hollow protrusions that faces the first hollowprotrusion with the first connection member of the connection memberstherebetween.

BRIEF DESCRIPTION OF THE DRAWINGS

Features will be apparent to those of skill in the art by describing indetail exemplary embodiments with reference to the attached drawings inwhich:

FIG. 1 is an exploded perspective view of a battery pack according to anembodiment;

FIGS. 2 and 3 illustrate perspective views of battery cells of FIG. 1 ;

FIG. 4 is a view of the battery cell of FIG. 3 and showing cooling flowpaths;

FIG. 5 is a view of an arrangement of multiple bus bars or an electricalconnection of battery cells in which multiple bus bars are arranged;

FIGS. 6A to 6C are views of electrical connections according to acomparative example;

FIG. 7 is an exploded perspective view of a structure of a cell holderin which battery cells are assembled;

FIG. 8 is an exploded perspective view of an exhaust hole and an exhaustpipe of FIG. 7 ;

FIG. 9 is a view of assembly of a bus bar and a cell holder;

FIG. 10 is a view of a structure of a circuit board illustrated in FIG.1 ;

FIG. 11 is a view of a potting resin and an adhesive resin respectivelyformed in a filling hole and a coupling opening region of FIG. 10 ;

FIG. 12 is a cross-sectional view taken along line XII-XII of FIG. 10 ;

FIG. 13 is a view of first and second opening regions of FIG. 10 ;

FIGS. 14 and 15 illustrate a separation member of FIG. 1 showingopposite surfaces of upper and lower separation members, respectively;

FIG. 16 is a view of a spatial separation of a cooling medium and anexhaust path of a cooling flow path, which is made by the separationmember; and

FIG. 17 is a perspective view of an upper duct and a lower duct.

DETAILED DESCRIPTION

Example embodiments will now be described more fully hereinafter withreference to the accompanying drawings; however, they may be embodied indifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey exemplary implementations to those skilled in the art.

In the drawing figures, the dimensions of layers and regions may beexaggerated for clarity of illustration. It will also be understood thatwhen a layer or element is referred to as being “on” another layer orelement, it can be directly on the other layer or element, orintervening layers may also be present. In addition, it will also beunderstood that when a layer is referred to as being “between” twolayers, it can be the only layer between the two layers, or one or moreintervening layers may also be present. Like reference numerals refer tolike elements throughout.

As used herein, the terms “or” and “and/or” include any and allcombinations of one or more of the associated listed items. Expressionssuch as “at least one of,” when preceding a list of elements, modify theentire list of elements and do not modify the individual elements of thelist.

FIG. 1 is an exploded perspective view of a battery pack according to anembodiment; FIGS. 2 and 3 illustrate perspective views of battery cellsof FIG. 1 ; FIG. 4 is a view of the battery cell of FIG. 3 and showingcooling flow paths; FIG. 5 is a view of an arrangement of multiple busbars or an electrical connection of battery cells in which multiple busbars are arranged; FIGS. 6A to 6C are views schematically showingelectrical connections according to a comparative example; FIG. 7 is anexploded perspective view of a structure of a cell holder in whichbattery cells are assembled; FIG. 8 is an exploded perspective view ofan exhaust hole and an exhaust pipe illustrated in FIG. 7 ; FIG. 9 is aview of assembly of a bus bar and a cell holder; FIG. 10 is a view of astructure of a circuit board of FIG. 1 ; FIG. 11 is a view of a pottingresin and an adhesive resin respectively formed in a filling hole and acoupling opening region of FIG. 10 ; FIG. 12 is a cross-sectional viewtaken along line XII-XII of FIG. 10 ; FIG. 13 is a view of first andsecond opening regions of FIG. 10 ; FIGS. 14 and 15 illustrate aseparation member of FIG. 1 showing opposite surfaces of upper and lowerseparation members, respectively; FIG. 16 is a view of a spatialseparation of a cooling medium and an exhaust path of a cooling flowpath, which is made by the separation member; and FIG. 17 is aperspective view of an upper duct and a lower duct.

Referring to FIGS. 9 and 10 , a battery pack according to an embodimentmay include a plurality of battery cells 10 and a plurality of bus bars120. Each bus bar 120 of the plurality of bus bars 120 may electricallyconnect different two battery cells 10 (among the plurality of batterycells 10) and may include coupling pieces 120 a at both ends (e.g.,opposite ends) thereof that are coupled to the two battery cells 10, anda protruding connecting piece 120 c at the center thereof that connectsthe coupling pieces 120 c at both ends. The battery pack may furtherinclude a circuit board 130 on the plurality of bus bars 120 andelectrically connected to at least a portion of the plurality of batterycells 10. The circuit board 130 may include escape holes 132 a thatexpose the protruding connection pieces 120 c.

Hereinafter, the battery pack according to an embodiment will bedescribed in more detail.

Referring to FIGS. 2 to 5 , the battery cell 10 may include the upperend portion 10 a and the lower end portion 10 b along a height (e.g.,longest axis) direction, and may be a circular battery cell 10 includinga cylindrical circumference (e.g., wall) 10 c between the upper endportion 10 a and the lower end portion 10 b. First and second electrodes11 and 12 with opposite polarities may be formed at the upper endportion 10 a and the lower end portion 10 b of the battery cell 10,respectively. In an implementation, the first and second electrodes 11and 12 of the battery cell 10 may correspond to a first polarity (e.g.,a negative electrode) and a second polarity (e.g., a positive electrode)of the battery cell 10, respectively, that are opposite to each other.In an implementation, any one of the upper end portion 10 a and thelower end portion 10 b of the battery cell 10, e.g., the lower endportion 10 b, may entirely form the first electrode 11, and a centralportion of the other end portion, for example, the upper end portion 10a, may form the second electrode 12 while the edge portion thereof mayform the first electrode 11. In an implementation, in the battery cell10 shown in FIG. 3 , the entire lower end portion 10 b and the edgeportion of the upper end portion 10 a may be covered by a can N thatintegrally extends, thus the entire lower end portion 10 b and the edgeportion of the upper end portion 10 a may have the same polarity andform the first electrode 11, and the central portion of the upper endportion 10 a corresponding to a cap assembly E that is electricallyinsulated from the can N forming the first electrode 11 may form thesecond electrode 12 having a polarity opposite to that of the firstelectrode 11.

In an implementation, a circuit board 130 that extends across aplurality of the battery cells 10 may include connection holes CH (seeFIG. 1 ) each exposing the edge portions of the upper end portions 10 aof a pair of adjacent battery cells 10, and the edge portions of theupper end portions 10 a of the battery cells 10 exposed by theconnection hole CH may form the first electrodes 11 having the samepolarity. In an implementation, the pair of adjacent battery cells 10exposed by the same connection hole CH may be arranged in a pattern inwhich one of the pair of adjacent battery cells 10 is inverted in theheight direction of the battery cells 10, however, the edge portions ofthe upper end portions 10 a of the pair of adjacent battery cells 10 mayform the first electrodes 11 having the same polarity regardless of thevertical arrangement of the battery cells 10. In an implementation, asillustrated in FIG. 3 , the can N forming the first electrode 11 mayextend from the edge portion of the upper end portion 10 a to the entirelower end portion 10 b, thus, regardless of the vertical arrangement ofthe battery cells 10, both the edge portions of the upper end portions10 a and the edge portions of the lower end portions 10 b of theadjacent battery cells 10 may form the first electrodes 11 having thesame polarity.

As described below, by way of bus bars 120, the upper end portions 10 aof the pair of adjacent battery cells 10 may be electrically connectedto each other, and the lower end portions 10 b of the pair of adjacentbattery cells 10 may be electrically connected to each other. In thiscase, the bus bars 120 may connect the central portions of the upper endportions 10 a of the pair of adjacent battery cells 10 to each other,and may connect the central portions of the lower end portions 10 b ofthe pair of adjacent battery cells 10 to each other. As illustrated inFIG. 3 , the central portion of the upper end portion 10 a may be formedas the cap assembly E forming the second electrode 12, the centralportion of the lower end portion 10 b may be formed as the can N formingthe first electrode 11, and the central portion of the upper end portion10 a of the battery cell 10 or the central portion of the lower endportion 10 b of the battery cell 10 may form the first electrode 11 orthe second electrode 12 according to the vertical arrangement. Throughthe present specification, in the case where the upper end portion 10 aand the lower end portion 10 b of the battery cell 10 form the firstelectrode 11 and the second electrode 12 or the second electrode 12 andthe first electrode 11, respectively, the central portion of the upperend portion 10 a of the battery cell 10 and the central portion of thelower end portion 10 b of the battery cell 10 may form the firstelectrode 11 and the second electrode 12 or the second electrode 12 andthe first electrode 11, respectively. In an implementation, in the casewhere the bus bars 120 connect the upper end portions 10 a and the lowerend portions 10 b of the pair of adjacent battery cells 10, the bus bars120 may connect the central portions of the upper end portions 10 a andthe lower end portions 10 b of the pair of adjacent battery cells 10 toeach other.

Through the present specification, the upper end portion 10 a and thelower end portion 10 b of the battery cell 10 may refer to an endportion at the top and an end portion at the bottom of the battery cell10 in the height direction, respectively, according to their positionsrather than the first electrodes 11 or the second electrodes 12 thatthey form. In an implementation, the upper end portions 10 a of the pairof adjacent battery cells 10 may form the first electrodes 11 or thesecond electrodes 12 such that the upper end portions 10 a have the sameelectrodes, or may form the first electrode 11 and the second electrode12 such that the upper end portions 10 a have the electrodes differentfrom each other, according to the arrangement of the battery cells 10.

Referring to FIG. 2 , according to an embodiment, the pair of adjacentbattery cells 10 may be arranged in a pattern in which one of thebattery cells 10 is inverted in the height direction, thus the upper endportions 10 a of the pair of adjacent battery cells 10 may form thefirst and second electrodes 11 and 12, and the lower end portions 10 bof the pair of adjacent battery cells 10 may also form the first andsecond electrodes 11 and 12.

Each of the pair of battery cells 10 adjacent to each other along anelectrical connection route, may be electrically connected to eachother, and the pair of adjacent battery cells 10 may be arranged in thepattern in which one of the pair of adjacent battery cells 10 isinverted in the height direction of the battery cells 10 such that thefirst and second electrodes 11 and 12 of the pair of adjacent batterycells 10 may be connected to each other in series. In an implementation,the first and second electrodes 11 and 12 may be connected to each otherin parallel. In an implementation, each of a group of the battery cells10 that constitutes the battery pack may be connected to the adjacentbattery cell 10 in series, and the battery pack according to anembodiment may not include a parallel connection between the pair ofadjacent battery cells 10. In an implementation, the battery pack mayinclude serial connections and/or parallel connections between theadjacent battery cells 10.

In an implementation, the pair of battery cells 10 adjacent to eachother along the electrical connection route may be arranged in a patternin which one of the battery cells 10 is vertically inverted, and thefirst and second electrodes 11 and 12 of the pair of adjacent batterycells 10 may be connected to each other in series, by connecting theupper end portions 10 a of the pair of adjacent battery cells 10 to eachother and the lower end portions 10 b of the pair of adjacent batterycells 10 to each other. In an implementation, the first and secondelectrodes 11 and 12 may be connected to each other in parallel.

Through the present specification, the electrical connection route ofthe battery cells 10 refers to directions in which the adjacent batterycells 10 are electrically connected to each other, rather than aspecific single direction, and may include different directions in whichthe adjacent battery cells 10 are connected to each other byarrangements of the bus bars 120.

In an implementation, the electrical connection route of the batterycells 10 may have a zigzag configuration. As will be described later,the battery cells 10 may be circular battery cells 10, and the batterycells 10 may be alternately arranged such that each of the battery cells10 is arranged in valley regions of the adjacent battery cells 10 inadjacent columns and thus, may be arranged densely. As described above,the plurality of battery cells 10 alternately arranged may beelectrically connected to each other by the plurality of bus bars 120arranged in zigzag patterns, and the electrical connection route may beformed in a zigzag configuration along the directions in which theplurality of bus bars 120 are arranged.

Referring to FIG. 2 , each of the group of the battery cells 10 thatconstitutes the battery pack may be electrically connected to each otheralong the electrical connection route in which the plurality of bus bars120 are arranged, and the battery cell 10 at one end and the batterycell 10 at the other end of the electrical connection route maycorrespond to a low-potential battery cell 10 having the lowestpotential and a high-potential battery cell 10 having the highestpotential, respectively, in the group of the battery cells 10. First andsecond output terminals 121 and 122 may be connected to thelow-potential battery cell 10 and the high-potential battery cell 10,respectively.

The first and second output terminals 121 and 122 may provide anelectrical connection between the group of battery cells 10 electricallyconnected to each other and an external device, and the group of batterycells 10 may supply discharge power to an external load through thefirst and second output terminals 121 and 122 or may receive chargepower from an external charger through the first and second outputterminals 121 and 122.

First and second fuse terminals 123 and 124 may be between the first andsecond output terminals 121 and 122 to be connected to a fuse box thatmay be between the first and second output terminals 121 and 122 toconstitute a charge/discharge path. The fuse box may constitute thecharge/discharge path between the first and second output terminals 121and 122, and thus, the charge/discharge path of the group of the batterycells 10 may pass through the fuse box through the first and second fuseterminals 123 and 124 connected to the fuse box. A fuse for blocking anovercurrent may be installed in the fuse box, and the charge/dischargepath may be blocked in response to the overcurrent.

In an implementation, the first and second fuse terminals 123 and 124may be connected to a pair of battery cells 10, respectively, that arebetween the low-potential battery cell 10 at the one end and thehigh-potential battery cell 10 at the other end of the electricalconnection route of the battery cells 10 along which the plurality ofbus bars 120 are arranged, and thus, the pair of battery cells 10 may beelectrically connected to each other through the fuse box connected tothe first and second fuse terminals 123 and 124. In an implementation,the first and second fuse terminals 123 and 124 may correspond to fuseterminals closest to the first and second output terminals 121 and 122,respectively, along the electrical connection route of the battery cells10 along which the plurality of bus bars 120 are arranged.

Cooling flow paths F may be between the pairs of adjacent battery cells10. A cooling medium flowing through the cooling flow paths F maycontact and cool the battery cells 10. The cooling flow paths F may passbetween the adjacent battery cells 10 in the height direction of thebattery cells 10 and extend to the outside of the battery cells 10, andthe cooling flow paths F to pass through substantially the entirebattery pack may be fluidly connected to the outside of the battery packthrough inlets and outlets of the cooling flow paths F. In this case,the cooling flow paths F may extend across the battery pack to passthrough substantially the entire battery pack along the height directionof the battery cells 10. The cooling flow path F will be described inmore detail later.

Referring to FIG. 3 , a vent portion 13 may be formed at at least one ofthe upper end portion 10 a and the lower end portion 10 b of the batterycell 10. In the case where the vent portion 13 is formed at one end ofthe battery cell 10, the vent portion 13 may be formed along an edgeportion of the one end of the battery cell 10. In an implementation, thevent portion 13 may be formed along an edge of the second electrode 12formed at the central portion of the one end of the battery cell 10, andmay be formed along the edge portion of the one end of the battery cell10.

In an implementation, a plurality of vent portions 13 spaced apart fromeach other may be formed along the edge portion of the one end of thebattery cell 10. The vent portion 13 is to relieve an internal pressureof the battery cell 10, and for example, the vent portion 13 may formedat a portion with a relatively low strength in the one end of thebattery cell 10. If the internal pressure of the battery cell 10 exceedsa predefined critical pressure (corresponding to a rupture pressure ofthe vent portion 13), the vent portion 13 may be ruptured to relieve theinternal pressure.

Referring to FIG. 1 , exhaust gas discharged through the vent portion 13by the internal pressure of the battery cell 10 may be discharged to theoutside of the battery pack along the exhaust gas path of which one sideis blocked by a blocking region 144 of a separation member 140. In animplementation, the blocking region 144 corresponding to the ventportions 13 of the battery cells 10 may be formed in the separationmember 140, and the exhaust gas discharged through the vent portions 13may be discharged to the outside of the battery pack through the exhaustgas path between the blocking region 144 of the separation member 140and the battery cells 10. The separation member 140 and the exhaust gaspath will be described in more detail later.

Hereinafter, the arrangements of the battery cells 10 and positions ofthe cooling flow paths F between the battery cells 10 according to anembodiment will be described with reference to FIG. 4 .

The cooling flow paths F may be formed between the adjacent batterycells 10. In an implementation, the battery cells 10 may be circularbattery cells 10, the battery cells 10 may be alternately arranged suchthat each of the battery cells 10 is arranged in valley regions of theadjacent battery cells 10 in adjacent columns and thus, may be arrangeddensely by utilizing spaces between the adjacent battery cells 10, andaccordingly dead spaces may be reduced and the battery pack may have arelatively high energy density compared to its area.

In an implementation, the battery cells 10 may be arranged along acolumn direction Z1 of the battery cells 10, and may be alternatelyarranged such that each of the battery cells 10 is arranged in valleyregions of the adjacent battery cells in adjacent columns. The columndirection Z1 of the battery cells 10 may refer to a direction in whichthe battery cells 10 are linearly arranged. The column direction Z1 ofthe battery cells 10 may be different from directions in which theplurality of battery cells 10 are electrically connected, that is, thedirections constituting the electrical connection route of the batterycells 10, and the column direction Z1 of the battery cells 10 may referto a direction in which the battery cells 10 are arranged, regardless ofelectrical connection states of the battery cells 10.

In an implementation, the battery cells 10 may be linearly arrangedalong the column direction Z1, and may be arranged in a zigzagconfiguration along a row direction perpendicular to the columndirection Z1. In an implementation, the battery cells 10 having thecircumferences adjacent to each other may be linearly arranged along thecolumn direction Z1, and may be arranged in the zigzag configurationalong the row direction perpendicular to the column direction Z1. Inthis case, the battery cells 10 having the circumferences adjacent toeach other may be arranged such that, e.g., in the group of the batterycells 10 that constitutes the battery pack, distances between thecircumstances of the adjacent battery cells 10 are equal to a minimumgap SG. In an implementation, the minimum gap SG may be set to secureelectrical insulation between the adjacent battery cells 10 andsufficient heat dissipation, and for example, the minimum gap SG may beabout 1 mm.

In an implementation, supposing that the group of battery cells 10 thatconstitutes the battery pack is surrounded by a rectangular envelope S1and S2 consisting of a pair of long side lines S1 and a pair of shortside lines S2 that extend to linearly surround the circumference of thegroup of battery cells 10, the column direction Z1 in which the batterycells 10 are linearly arranged may correspond to a direction parallel tothe long sides S1 of the envelope S1 and S2, and the row direction inwhich the battery cells 10 are arranged in the zigzag configuration maycorrespond to a direction similar to the short sides S2 of the envelopeS1 and S2.

Referring to FIG. 4 , the battery cells 10 of first and second columnsR1 and R2 may be densely arranged such that the battery cells 10 of thefirst column R1 are in valley regions of the battery cells 10 of thesecond column R2, and similarly, the battery cells 10 of the secondcolumn R2 and a third column R3 may be densely arranged such that thebattery cells 10 of the second column R2 are in valley regions of thebattery cells 10 of the third column R3.

Each of the battery cells 10 may be in the valley regions of the (e.g.,pairs of) adjacent battery cells 10, thus the circumferences of threebattery cells 10 may be adjacent to each other around the battery cells10, and the cooling flow path F may be formed between the three batterycells 10. The cooling flow path F may be formed in a spare regionbetween the three battery cells 10, of which circumferences are adjacentto each other, that is not occupied by the battery cells 10, that is, avalley region.

In an implementation, the cooling flow paths F may be formed between thebattery cells 10 of the first column R1 and the battery cells 10 of thesecond column R2 adjacent to each other, and one cooling flow path F maybe formed between two battery cells 10 of the first column R1 and onebattery cell 10 of the second column R2, and one cooling flow path F maybe formed between two battery cells 10 of the second column R2 and onebattery cell 10 of the first column R1. Similarly, the cooling flowpaths F may be formed between the battery cells 10 of the second columnR2 and the battery cells 10 of the third column R2 adjacent to eachother, and one cooling flow path F may be formed between two batterycells 10 of the second column R2 and one battery cell 10 of the thirdcolumn R3, and one cooling flow path F may be formed between two batterycells 10 of the third column R3 and one battery cell 10 of the secondcolumn R2.

Referring to FIG. 4 , six cooling flow paths F may be formed along thecircumferential direction of one battery cell 10 of the second columnR2. In an implementation, one battery cell 10 of the second column R2may form a plurality of valley regions between six battery cells 10 (thebattery cells 10 of the first to third columns R1, R2, and R3) along thecircumferential direction, may form a total of six valley regionsbetween every two battery cells 10 sequentially along thecircumferential direction, and may form a total of six cooling flowpaths F, one for each of the six valley regions.

Hereinafter, the arrangements of the plurality of bus bars 120 and theelectrical connection of the battery cells 10 in which the plurality ofbus bars 120 are arranged will be described with reference to FIGS. 4and 5 . For reference, in FIG. 5 , for convenience of understanding,upper bus bars (see FIG. 1 ) and lower bus bars (see FIG. 1 ) are showntogether, and the entire electrical connection by the upper bus bars andthe lower bus bars is shown. Hereinafter, the upper bus bar and thelower bus bar will be collectively referred to as the bus bar 120without being distinguished from each other. In an implementation, theelectrical connection shown in FIG. 5 may be implemented through theupper bus bars and the lower bus bars alternately arranged on upper andlower portions of a cell holder 110. The numbers in the circles shown inFIG. 5 may indicate an order of the battery cells 10 counted along theelectrical connection route.

Referring to FIGS. 4 and 5 , the plurality of bus bars 120 thatelectrically connect the pair of adjacent battery cells 10 may bearranged in a zigzag configuration. In an implementation, the batterycells 10 may be circular battery cells 10, and the battery cells 10 maybe alternately arranged such that each of the battery cells 10 isarranged in valley regions of the adjacent battery cells 10 in adjacentcolumns and thus, may be arranged densely.

In an implementation, supposing that the group of battery cells 10 thatconstitutes the battery pack is surrounded by the (e.g., imaginary)rectangular envelope S1 and S2 consisting of the pair of long side linesS1 and the pair of short side lines S2 that extend to linearly surroundthe circumference of the group of battery cells 10, the group of batterycells 10 that constitutes the battery pack may be configured inarrangements in the column direction Z1 that linearly extends inparallel with the direction of the long side line S1 and arrangements inthe row direction that extends in a zigzag shape similar to thedirection of the short side line S2. That is, the row direction thatextends in the zigzag shape may be similar to the direction Z2 of theshort side line S2, that is shorter than the long side line S1, ratherthan the direction Z1 of the long side line S1 of the group of batterycells 10. In this case, the plurality of bus bars 120 that electricallyconnect the adjacent battery cells 10 may be arranged in the zigzagshape while connecting the adjacent battery cells 10 along thearrangements of the battery cells 10 in the row direction that extendsin the zigzag shape.

In the present disclosure, the arrangements of the plurality of bus bars120 and the electrical connection route of the battery cells 10 alongwhich the bus bars 120 are arranged may be configured in the rowdirection similar to the direction Z2 of the short side line S2 shorterthan the long side line S1, rather than in the column direction Z1parallel to the direction of the long side line S1, thus potentialdifferences (voltages) between the battery cells 10 electricallyconnected to each other in one arrangement along the row direction andthe battery cells 10 electrically connected to each other in thearrangement adjacent to the one arrangement along the row direction maybe reduced, and for example, by reducing the potential differencesbetween the battery cells 10 in the adjacent arrangements along the rowdirection Z1, a risk of an electrical short between the adjacent batterycells 10 may be reduced and the safety of the battery pack may beimproved. The battery cells 10 in the one arrangement and the adjacentarrangement may be electrically connected to each other through the busbars 120 in an arrangement in the row direction that extends in thezigzag shape and may be arranged to be adjacent to each other along thecolumn direction Z1 perpendicular to the row direction. In this case, amaximum potential difference (maximum voltage) between the battery cells10 adjacent to each other along the column direction Z1 in the adjacentarrangements, for example, a maximum potential difference (maximumvoltage) between the seventh battery cell 10 in the one arrangement andthe eighteenth battery cell 10 in the arrangement adjacent to the onearrangement may be calculated by multiplying the number of the bus bars120 that electrically connect the two battery cells 10, that is, 11, bya full charge voltage of each of the battery cells 10, that is 4.2 V,since a difference equal to the full charge voltage may occur betweentwo adjacent battery cells 10 connected by the bus bar 120. According toan embodiment, the maximum potential difference (maximum voltage)between the two adjacent battery cells 10, the seventh and eighteenthbattery cells 10, may be 46.2 V. As will be described below, the batterypack according to an embodiment may have a 72-cell structure in which 72battery cells 10 are configured, and may include a high-voltageexcursion HVe for compatibility with a 64-cell structure in which 64battery cells 10 are configured, in which case, a maximum potentialdifference (maximum voltage) between two adjacent battery cells 10, thenineteenth and fortieth battery cells 10, may be 88.2 V. It may bedetermined that the safety of the battery pack is improved, in that incomparative examples shown in FIGS. 6A to 6C, maximum potentialdifferences (maximum voltages) between the two adjacent battery cells 10are greater than 200 V or approaches 200 V.

If the arrangements of the plurality of bus bars 120 were to beconfigured along the column direction Z1 rather than the row direction,the number of pairs of adjacent battery cells 10 arranged along thecolumn direction Z1, in which each pair of adjacent battery cells 10 areelectrically connected to each other through the bus bar 120, is greaterthan the number of pairs of adjacent battery cells 10 arranged along therow direction, thus the number of bus bars 120 arranged along the columndirection Z1 is also greater than the number of bus bars 120 arrangedalong the row direction, and accordingly, the maximum voltage betweenthe adjacent battery cells 10 increases, resulting in an increased riskof an electrical short between the adjacent battery cells 10.

Referring to FIG. 5 , according to an embodiment, a group of the busbars 120 that constitutes the battery pack may include the bus bars 120extending in a zigzag shape along the row direction and the bus bars 120extending along the column direction Z1, however, the arrangements ofthe bus bars 120 and the electrical connection route of the batterycells 10 along which the bus bars 120 are arranged may be regarded asbeing along the row direction. In an implementation, whether the groupof the bus bars 120 that constitute the battery pack is arranged alongthe row direction or the column direction Z1 may be determined bycomparing the number of the bus bars 120 along the row direction and thenumber of the bus bars 120 along the column direction Z1, and accordingto an embodiment, one bus bar 120 along the column direction Z1 may bearranged per approximately five bus bars 120 along the row direction,thus the arrangements of the bus bars 120 and the electrical connectionroute of the battery cells 10 along which the bus bars 120 are arrangedmay be regarded as being along the row direction rather than the columndirection Z1.

In an implementation, the arrangements of the bus bars 120 and theelectrical connection route of the battery cells 10 along which the busbars 120 are arranged may be configured along the row direction thatextends in a zigzag shape, and the arrangement, as one unit, in whichthe bus bars 120 extend along the row direction may be repeatedlyconfigured along the column direction Z1, and in this case, the firstand second output terminals 121 and 122 may be arranged along the columndirection Z1, that is, the direction of the long side lines of theenvelope S1 and S2. The first and second output terminals 121 and 122may be arranged in the direction Z1 of the long side lines of theenvelope S1 and S2 that surrounds the group of the battery cells 10,thus electrical connections may be established along the row directionthat is similar to the direction Z2 of the short side lines of theenvelope S1 and S2, and accordingly, the maximum potential differences(maximum voltages) between the adjacent battery cells 10 may be reduced.

As illustrated in FIGS. 6A to 6C, if the first and second outputterminals 121 and 122 were to be arranged along the direction Z2 of theshort side lines of the envelope S1 and S2 that surrounds the group ofthe battery cells 10, the voltage of the adjacent battery cells 10 maybe relatively increased as compared with the embodiment illustrated inFIG. 5 , and maximum potential differences (maximum voltages) may begenerated at portions indicated by the ellipses in FIGS. 6A to 6C, andthe maximum potential differences (maximum voltages) may be greater than200 V or may approach 200 V. In the comparative examples illustrated inFIGS. 6A to 6C, the maximum potential differences (maximum voltages) are210 V, 180.6 V, and 273 V, respectively.

In the comparative examples illustrated in FIGS. 6A to 6C, thearrangements of the bus bars 120 or the electrical connection route ofthe battery cells 10 along which the bus bars 120 are arranged areconfigured along the column direction Z1 parallel to the direction ofthe long side lines of the envelope S1 and S2 rather than the rowdirection similar to the direction Z2 of the short side lines of theenvelope S1 and S2, and thus, the potential differences between theadjacent battery cells 10 and the risk of an electrical short betweenthe adjacent battery cells 10 may increase. In the comparative exampleillustrated in FIG. 6C, although the electrical connection route of thebattery cells 10 is configured along the row direction similar to thedirection Z2 of the short side lines of the envelope S1 and S2, thearrangement, as one unit, in which the bus bars 120 extend along the rowdirection is repeatedly configured along the column direction Z1parallel to the direction Z1 of the long side lines of the envelope S1and S2 while reciprocating along the column direction Z1, and thus, themaximum potential difference (maximum voltage) between the pair ofadjacent battery cells 10 in the portion indicated by the eclipse mayincrease. In an implementation, as illustrated in FIG. 5 , thearrangement in which the bus bars 120 extend along the row direction maybe repeatedly configured along the column direction Z1 parallel to thedirection Z1 of the long side lines of the envelope S1 and S2, from oneshort side line S2 to the other short side line S2 of the envelope S1and S2 unidirectionally without reciprocating.

Referring to FIG. 5 , according to an embodiment, the group of bus bars120 and the group of battery cells 10 that constitute the battery packmay be divided into a low-voltage area LV that encompasses from thefirst output terminal 121 connected to the low-potential battery cell 10having the lowest potential to the first fuse terminal 123, and ahigh-voltage area HV that encompasses from the second output terminal122 connected to the high-potential battery cell 10 having the highestpotential to the second fuse terminal 124. In this case, the first andsecond fuse terminals 123 and 124 may correspond to the fuse terminals,which are connected to the fuse box (not shown), closest to the firstand second output terminals 121 and 122, respectively, along theelectrical connection route of the battery cells 10, and may beconnected to the first and second output terminals 121 and 122 along theelectrical connection route without passing through the fuse box.

In an implementation, the boundary between the low-voltage area LV andthe high-voltage area HV may be asymmetrical with respect to the line Oin FIG. 5 passing between the first and second fuse terminals 123 and124, and parallel to the direction Z2 of the short side lines of theenvelope S1 and S2. For example, the high-voltage area HV may include ahigh-voltage excursion HVe that passes the line O to extend toward thelow-voltage area LV along the direction Z1 of the long side lines of theenvelope S1 and S2, and the low-voltage area LV may include alow-voltage excursion LVe aligned toward the opposite side of thehigh-voltage excursion HVe to be elongated along the direction Z2 of theshort side lines while avoiding the high-voltage excursion HVe. In animplementation, the high-voltage excursion HVe and the low-voltageexcursion LVe may be arranged at positions opposite to each other alongthe direction Z2 of the short side lines of the envelope S1 and S2, thelow-voltage excursion LVe may be arranged at one position relativelyclose to the first and second fuse terminals 123 and 124 along thedirection Z2 of the short side lines of the envelope S1 and S2, and thehigh-voltage excursion HVe may be arranged at another positionrelatively far from the first and second fuse terminals 123 and 124. Inan implementation, the high-voltage excursion HVe and the low-voltageexcursion LVe may extend along the direction Z1 of the long side linesand the direction Z2 of the short side lines of the envelope S1 and S2,respectively, to be elongated along the respective directions. In animplementation, the high-voltage excursion HVe may be elongated alongthe direction Z1 of the long side lines rather than the direction Z2 ofthe short side lines to extend toward the low-voltage area LV, and thelow-voltage excursion LVe may be elongated along the direction Z2 of theshort side lines rather than the direction Z1 of the long side lineswhile avoiding the high-voltage excursion HVe.

In an implementation, the high-voltage area HV and the low-voltage areaLV may be asymmetrical with respect to the line O, and compatibility ofa battery management system (BMS) with the 64-cell structure in which 64battery cells 10 are configured and the 72-cell structure in which 72battery cells 10 are configured may be provided. In an implementation,the battery management system (BMS) has a pin-map corresponding to thepositions of the battery cells 10 and the fuse box, and in the 64-cellstructure, the fuse box (not shown) is located between a pin of number32 (the thirty-second battery cell along the electrical connection routeof the battery cells 10) and a pin of number 33 (the thirty-thirdbattery cell along the electrical connection route of the battery cells10). In an implementation, in the 64-cell structure, the fuse box may belocated a central position, that is, between the thirty-second batterycell 10 and the thirty-third battery cell 10 along the electricalconnection route of the battery cells 10.

In an implementation, like the 64-cell structure, the 72-cell structureshown in FIG. 5 may be implemented such that the fuse box is locatedbetween the pin of number 32 (the thirty-second battery along theelectrical connection route of the battery cells 10) and pin of number33 (the thirty-third battery cell along the electrical connection routeof the battery cells 10), and the battery management system (BMS) may beutilized in common in the 64-cell structure and the 72-cell structure.That is, the battery management system (BMS) having a specific pin-mapmay be applied in common to the 64-cell structure and the 72-cellstructure.

In the 72-cell structure designed to have the compatibility of thebattery management system (BMS) with the 64-cell structure according toan embodiment, the number of the bus bars 120 in the high-voltage areaHV (or the number of the battery cells 10 in the high-voltage area HV)may be greater than the number of the bus bars 120 in the low-voltagearea LV (or the number of the battery cells 10 in the low-voltage areaLV), based on the fuse box (not shown) as a boundary along theelectrical connection route of the battery cells 10, and thehigh-voltage area HV including the number of the bus bars 120 greaterthan that of the low-voltage area LV may include the high-voltageexcursion HVe that extends toward the low-voltage area LV, while thelow-voltage area LV may include the low-voltage excursion LVe to avoidthe high-voltage excursion HVe.

Referring to FIG. 7 , the battery cells 10 may be assembled in the cellholder 110. In an implementation, the cell holder 110 may have one(e.g., first) side in which the battery cells 10 are assembled, andanother (e.g., second) side on which hollow protrusions 115 connected tothe cooling flow paths F between the battery cells 10 adjacent to eachother are formed. As described below, the hollow protrusion 115 mayextend to penetrate the circuit board 130 on the other side of the cellholder 110. Hereinafter, the cell holder 110 will be described in moredetail.

The cell holder 110 may include an upper holder 110 a into which theupper end portions 10 a of the battery cells 10 are inserted and a lowerholder 110 b into which the lower end portions 10 b of the battery cells10 are inserted. Except for the upper end portions 10 a and the lowerend portions 10 b of the battery cells 10 inserted into the upper holder110 a and the lower holder 110 b, respectively, central portions of thebattery cells 10 in the height direction may be exposed between theupper holder 110 a and the lower holder 110 b. The cooling flow paths Fmay be formed between the battery cells 10 adjacent to each other, andthe central portions of the battery cells 10 exposed between the upperholder 110 a and the lower holder 110 b may be directly exposed to acooling medium flowing through the cooling flow paths F and thus, may becooled. In an implementation, the cooling medium may be low temperatureair introduced from the outside of the battery pack. In animplementation, the cooling medium may be a cooling medium in a gasstate other than air, e.g., a refrigerant gas.

Assembly ribs 111 into which the upper end portions 10 a of the batterycells 10 and the lower end portions 10 b of the battery cells 10 areinserted may be formed in the upper holder 110 a and the lower holder110 b, respectively, and the assembly rib 111 may restrict an assemblyposition of the battery cell 10 while surrounding the upper end portion10 a or the lower end portion 10 b of the battery cell 10. The assemblyrib 111 may protrude from a plate-shaped main body of the cell holder110 toward the battery cell 10 in the height direction of the batterycell 10, and may support the battery cell 10 while surrounding the upperend portion 10 a or the lower end portion 10 b of the battery cell 10.

Terminal holes 112 that expose the first and second electrodes 11 and 12of the battery cells 10 may be formed in the cell holder 110. The firstand second electrodes 11 and 12 of the battery cell 10 exposed by theterminal hole 112 may be electrically connected to the adjacent batterycells 10 through the bus bars 120. In an implementation, the terminalhole 112 may be formed in a region surrounded by the assembly rib 111into which the upper end portion 10 a or the lower end portion 10 b ofthe battery cell 10 is inserted.

As illustrated in FIG. 3 , according to an embodiment, the vent portion13 may be formed at at least one of the upper end portion 10 a and thelower end portion 10 b of the battery cell 10, and the vent portion 13may be formed along the edge surrounding the second electrode 12 formedat the one end portion of the battery cell 10. Referring to FIG. 7 , theterminal hole 112 may have a sufficient size (e.g., diameter) to exposethe second electrode 12 of the battery cell 10 and the vent portion 13formed along the edge portion of the one end portion of the battery cell10. In an implementation, the pair of adjacent battery cells 10 may bearranged in the pattern in which one of the pair of the battery cells 10is inverted in the height direction, accordingly, the vent portion 13 ofthe battery cell 10 may be formed at the upper end portion 10 a or thelower end portion 10 b of the battery cell 10 according to a position ofthe battery cell 10, and in this case, the terminal holes 112 formed atthe upper and lower holders 110 a and 110 b may have a sufficient size(e.g., diameter) to expose the vent portions 13 formed at the upper endportions 10 a and the lower end portions 10 b of the battery cells 10,respectively.

Referring to FIG. 7 , the exhaust gas discharged through the ventportions 13 of the battery cells 10 may flow along the exhaust gas pathformed on the cell holder 110 through the terminal holes 112 of the cellholder 110, and may be discharged to the outside of the battery packthrough an exhaust hole DH formed at one side of the cell holder 110. Inan implementation, the exhaust hole DH may be formed at one side of thecell holder 110, and the exhaust hole DH may be fluidly connected to thevent portions 13 of the plurality of battery cells 10 to collect theexhaust gas discharged from the vent portions 13 and discharge thecollected exhaust gas to the outside of the battery pack. In animplementation, the exhaust hole DH may be formed at an edge of the cellholder 110, and may be formed at one edge of the cell holder 110 alongthe direction of long side lines of the cell holder 110.

The direction of the long side lines of the cell holder 110 maycorrespond to the direction Z1 of the long side lines of the envelope S1and S2 (refer to FIG. 4 ) that surrounds the group of the battery cells10 that constitutes the battery pack. In an implementation, supposingthat the group of battery cells 10 that constitutes the battery pack issurrounded by the rectangular envelope S1 and S2 (see FIG. 4 )consisting of the pair of long side lines S1 and the pair of short sidelines S2 that extend to linearly surround the circumference of the groupof battery cells 10, the direction Z1 of the long side lines of theenvelope S1 and S2 may correspond to the direction of the long sidelines of the cell holder 110.

Referring to FIG. 7 , according to an embodiment, a plurality of batterycells 10 may be arranged in the pattern in which one of the pair ofadjacent battery cells 10 is inverted in the height direction of thebattery cells 10. In an implementation, the plurality of battery cells10 may include a first group and a second group of the battery cells 10,such that the battery cells 10 of the first group are verticallyinversed or inverted relative to the battery cells 10 of the secondgroup. In an implementation, the battery cells 10 of the first group mayhave the vent portions 13 formed at the upper end portions 10 a thereof,and the battery cells 10 of the second group may have the vent portions13 formed at the lower end portions 10 b thereof.

Referring to FIGS. 7 and 8 , the cell holder 110 may include the upperholder 110 a in which the upper end portions 10 a of the battery cells10 of the first group are assembled, and the lower holder 110 b in whichthe lower end portions 10 b of the battery cells 10 of the second groupare assembled, and according to an embodiment, the upper holder 110 aand the lower holder 110 b may be assembled with each other with thebattery cells 10 of the first and second groups interposed therebetween,thereby providing an accommodation space for the battery cells 10 of thefirst and second groups. In this case, an upper exhaust hole DHa,through which the exhaust gas discharged from the upper end portions 10a (e.g., the vent portion 13) of the battery cells 10 of the first group10 is collected, may be formed at an upper side of the upper holder 110a, and a lower exhaust hole DHb, through which the exhaust gasdischarged from the lower end portions 10 b (e.g., the vent portion 13)of the battery cells 10 of the second group 10 is collected, may beformed at a lower side of the lower holder 110 b. Here, the exhaust gaspath connecting the upper end portions 10 a (e.g., the vent portion 13)of the battery cells 10 of the first group to the upper exhaust hole DHamay be formed on the upper side of the upper holder 110 a, and theexhaust gas path connecting the lower end portions 10 b (e.g., the ventportion 13) of the battery cells 10 of the second group to the lowerexhaust hole DHb may be formed on the lower side of the lower holder 110b. Referring to FIG. 1 , an upper separation member 140 a and a lowerseparation member 140 b that form the respective exhaust gas paths maybe arranged on the upper side of the upper holder 110 a and the lowerside of the lower holder 110 b, and the exhaust gas paths may be formedbetween the upper side of the upper holder 110 a and the upperseparation member 140 a and between the lower side of the lower holder110 b and the lower separation member 140 b, respectively. In animplementation, the exhaust gas paths may be formed between the upperside of the upper holder 110 a and the blocking region 144 of the upperseparation member 140 a and between the lower side of the lower holder110 b and the blocking region 144 of the lower separation member 140 b.The upper separation member 140 a, the lower separation member 140 b,and the blocking region 144 will be described in more detail later.

Referring to FIGS. 7 and 8 , the upper exhaust hole DHa and the lowerexhaust hole DHb may be formed at edge positions of the upper holder 110a and the lower holder 110 b that correspond to each other, e.g., atedge positions along the direction of the long side lines the cellholder 110. In addition, an exhaust duct DD may be formed at the edgepositions of the upper holder 110 a and the lower holder 110 b at whichthe upper exhaust hole DHa and the lower exhaust hole DHb are formed,while continuously extending in the height direction. The exhaust ductDD may be continuously formed through the upper holder 110 a and thelower holder 110 b in the height direction, more specifically, as theupper holder 110 a and the lower holder 110 b are assembled, a portionof the exhaust duct DD formed in the upper holder 110 a and anotherportion of the exhaust duct DD formed in the lower holder 110 b may beconnected to each other, and thus, the complete exhaust duct DD may beformed in a tube shape. In an implementation, the exhaust duct DD mayinclude the portion formed in the upper holder 110 a and another portionformed in the lower holder 110 b such that the exhaust duct DD isdivided into the two portions formed in the upper holder 110 a and thelower holder 110 b, respectively. For reference, throughout the presentspecification, the term “height direction” may refer to the heightdirection of the battery cell 10, and may refer to a lengthwisedirection of the battery cell 10, e.g., the direction of the longestdimension or long axis of the battery cell 10.

The exhaust duct DD may form a space separated from the accommodationspace for the battery cells 10 formed by assembling the upper holder 110a and the lower holder 110 b, and may have a sealed structure except forportions connected to the upper exhaust hole DHa and the lower exhausthole DHb through which the exhaust gas is introduced, and a portionconnected to an exhaust pipe DP through which the exhaust gas isdischarged to the outside of the cell holder 110.

The upper exhaust hole DHa and a lower exhaust hole DHb may be connectedto both ends of the exhaust duct DD in the height direction. Inaddition, the exhaust pipe DP may be connected to a location betweenboth ends of the exhaust duct DD in the height direction. In animplementation, the exhaust duct DD may continuously extend through theupper holder 110 a and the lower holder 110 b in the height direction,may be connected to the upper exhaust hole DHa and the lower exhausthole DHb at both ends, respectively, and may be connected to, at thelocation between both ends in the height direction, the exhaust pipe DPfor collecting the exhaust gas discharged from the upper exhaust holeDHa and the lower exhaust hole DHb and discharging the collected exhaustto the outside of the cell holder 110. In this case, the exhaust pipe DPmay be connected to the exhaust duct DD at a location between the upperside and the lower side of the cell holder 110 in the height direction,may protrude from the location between the upper side and the lower sideof the cell holder 110 toward the outside, and for example, may protrudefrom an outer surface of the cell holder 110 toward the outside alongthe direction of the long side line of the cell holder 110. In animplementation, the exhaust pipe DP may be formed at a location betweenthe upper side of the upper holder 110 a and the lower side of the lowerholder 110 b, and may be formed at a location of the upper holder 110 a,the location being closer to the upper side of the upper holder 110 athan the lower side, or at a location of the lower holder 110 b, thelocation being closer to the lower side of the lower holder 110 b thanthe upper side. In an implementation, the exhaust pipe DP may beprotrude from the upper holder 110 a toward the outside, and may beformed at a location between the upper side of the upper holder 110 aand the lower side of the lower holder 110 b, the location being closerto the upper side of the upper holder than the lower side of the lowerholder 110 b. As illustrated in FIG. 1 , according to an embodiment, thecircuit board 130 may arranged on the upper holder 110 a, the circuitboard 130 may be between the upper side of the upper holder 110 a andthe upper separation member 140 a which form the exhaust gas paththerebetween, and may generate a flow resistance on the exhaust gaspath, and the exhaust pipe DP may be formed at a location between theupper side of the upper holder 110 a and the lower side of the lowerholder 110 b, the location being closer to the upper side of the upperholder 110 a than the lower side of the lower holder 110 b, to allow theflow resistance to be balanced between the exhaust gas path of the upperholder 110 a and the exhaust gas path of the lower holder 110 b. Asillustrated in FIG. 1 , in the case where the circuit board 130 isarranged on the upper holder 110 a and the upper exhaust hole DHa isformed at the upper side of the upper holder 110 a, the upper exhausthole DHa may be formed at a location deviated from the circuit board130, and accordingly, the flow of the exhaust gas introduced into theupper exhaust hole DHa may not be disturbed by the circuit board 130.The circuit board 130 may be arranged on the upper holder 110 a and mayoverlap a partial area of the upper holder 110 a rather than the entirearea, and thus, the upper exhaust hole DHa may be formed at an area ofthe upper holder 110 a that is not covered by the circuit board 130 toprevent the upper exhaust hole DHa from being blocked by the circuitboard 130.

Referring to FIG. 8 , the exhaust pipe DP may form an end of the exhaustgas path through which the exhaust gas discharged from the battery cells10 of the first and second groups accommodated in the cell holder 110 isdischarged to the outside of the cell holder 110. Through the presentspecification, the upper exhaust hole DHa, the lower exhaust hole DHb,and the exhaust duct DD are described as separate components, but thisis for convenience of understanding, and both ends of the exhaust ductDD that continuously extends through the upper holder 110 a and thelower holder 110 b in the height direction may form the upper exhausthole DHa and the lower exhaust hole DHb, and the upper exhaust hole DHa,the lower exhaust hole DHb, and the exhaust duct DD may be formedtogether in a single pipe shape that continuously extends in the heightdirection.

Referring to FIG. 7 , the hollow protrusions 115 that form the coolingflow paths F may be formed at the cell holder 110. The hollow protrusion115 may include a central hollow portion forming the cooling flow path Fand a wall body 115 a surrounding the central hollow portion. In animplementation, the hollow protrusion 115 may include a circular wallbody 115 a surrounding the central hollow portion. In an implementation,the circular wall body 115 a of the hollow protrusion 115 may refer to ashape of an outer circumference of the hollow protrusion 115, and aninner circumference of the hollow protrusion 115 may have a shape otherthan a circular shape. In an implementation, the circular wall body 115a of the hollow protrusion 115 may have the outer circumference in acircular shape and the inner circumference in a shape of a triangle withrounded edges. In an implementation, the hollow protrusion 115 mayinclude the wall body 115 a that surrounds the central hollow portionand has the outer circumference in any one of various shapes including apolygon, an ellipse, and a hexagon, and the inner circumference in anyone of various shapes including a circle, an ellipse, a polygon, and acombination thereof.

The hollow protrusion 115 may protrude from the plate-shaped main bodyof the cell holder 110, in a direction away from the battery cells 10.In an implementation, the hollow protrusions 115 may extend the coolingflow paths F formed between the adjacent battery cells 10 to the outsideof the battery cells 10 in the height direction of the battery cells 10and may form the cooling flow paths F each surrounded by the wall body115 a. In an implementation, positions of the hollow protrusions 115formed along the plate-shaped main body of the cell holder 110 maycorrespond to the positions of the cooling flow paths F formed betweenthe battery cells 10, the positions of the hollow protrusions 115 maycorrespond to the positions of the cooling flow paths F described withreference to FIG. 4 , and the positions of the cooling flow paths F inFIG. 4 may refer to the positions of the hollow protrusions 115.

Referring to FIG. 1 , the hollow protrusion 115 may pass through thecircuit board 130 and the separation member 140 that are arranged on theupper holder 110 a sequentially in the height direction of the batterycells 10, which in case, the hollow protrusion 115 may form the coolingflow path F that extends across the battery pack to pass throughsubstantially the entire battery pack in the height direction of thebattery cells 10. In an implementation, the hollow protrusion 115 of theupper holder 110 a may pass through the circuit board 130 and the upperseparation member 140 a that are arranged on the upper holder 110 asequentially in the height direction of the battery cells 10, and thehollow protrusion 115 of the lower holder 110 b may pass through thelower separation member 140 b that is arranged under the lower holder110 b in the height direction of the battery cells 10. Open regions 135and 145 into which the hollow protrusions 115 are inserted may be formedat the circuit board 130 and the separation member 140. The open regions135 and 145 of the circuit board 130 and the separation member 140 maybe formed such that positions in the circuit board 130 and theseparation member 140 corresponding to the hollow protrusions 115 areopened. The open regions 135 and 145 of the circuit board 130 and theseparation member 140 will be described in more detail below.

Referring to FIGS. 1 and 2 , the bus bars 120 may be arranged on thecell holder 110. In an implementation, the upper bus bars and the lowerbus bars may be arranged on the upper holder 110 a and the lower holder110 b, respectively, and the bus bars 120 may be alternately arranged onthe upper holder 110 a and the lower holder 110 b to connect the pair ofbattery cells 10 adjacent to each other along the electrical connectionroute. As described above, each of the bus bars 120 may electricallyconnect the pair of battery cells 10 along the electrical connectionroute, and the plurality of bus bars 120 may be arranged along theelectrical connection route of the battery cells 10 to electricallyconnect a group of the battery cells 10.

Referring to FIG. 9 , the bus bar 120 may include coupling pieces 120 aat both ends thereof, a central protruding connection piece 120 c thatconnects the coupling pieces 120 a to each other, and bent portions 120b that connect the coupling pieces 120 a to the central protrudingconnection piece 120 c in a bent shape. The coupling pieces 120 a atboth ends of the bus bar 120 may be coupled to the upper end portions 10a or the lower end portions 10 b of the pair of adjacent battery cells10, and may be coupled to the upper end portions 10 a or the lower endportions 10 b of the pair of adjacent battery cells 10 exposed by theterminal holes 112 of the cell holder 110 to connect the first andsecond electrodes 11 and 12 of the pair of adjacent battery cells 10 inseries or in parallel. In an implementation, the coupling pieces 120 aat both ends of the bus bar 120 may be welded to the battery cellsadjacent to each other 10.

The bent portions 120 b may connect the coupling pieces 120 a (at bothends) to the central protruding connection piece 120 c in the bentshape, and may help support the protruding connection piece 120 c at alevel spaced apart from the battery cells 10 in the height direction ofthe battery cells 10, thereby reducing or preventing electricalinterference between the protruding connection piece 120 c and thebattery cells 10 and pressing the coupling pieces 120 a at both endstoward the upper end portions 10 a or the lower end portions 10 b of thebattery cells 10 while being elastically deformed by the protrudingconnection piece 120 c pressed toward the battery cells 10 by the cellholder 110 (e.g., the hollow protrusions 115). This will be described inmore detail below.

The protruding connection piece 120 c may be a flat plate-shaped memberor the bus bar 120 that is farthest from the battery cells 10 in theheight direction of the battery cells 10. The protruding connectionpiece 120 c may be on a virtual plane, e.g., of the bus bar 120, that isfarthest from the battery cell 10. In an implementation, as illustratedin FIG. 10 , the protruding connection piece 120 c may be exposed fromor through the circuit board 130 on the cell holder 110, e.g., theentire protruding connection piece 120 c may be exposed through thecircuit board 130 (e.g., in the solid portion of the circuit board 130)through an escape hole 132 a in the circuit board 130.

Referring to FIG. 9 , the bus bar 120 may extend between the hollowprotrusions 115 of the cell holder 110. In an implementation, the busbar 120 may extend across and between a pair of hollow protrusions 115,e.g., the protruding connection piece 120 c of the bus bar 120 may bebetween the pair of hollow protrusions 115. The extending (e.g.,lengthwise) direction of the bus bar 120 and the direction in which thepair of hollow protrusions 115 face each other may cross each other,e.g., may vertically cross each other.

In an implementation, the bus bar 120 may extend across or between apair of battery cells 10 of which circumferences are adjacent to eachother and may electrically connect the pair of adjacent battery cells 10to each other. In this case, the cooling flow paths F and the hollowprotrusions 115 may be between the pair of adjacent battery cells 10connected to each other by the bus bar 120 and another pair of batterycells 10 adjacent to each other in a direction intersecting the bus bar120. In an implementation, the bus bar 120 may extend between the pairof hollow protrusions 115 facing each other in the directionintersecting the bus bar 120.

A pair of locking steps 115 p (into which the bus bar 120 is inserted tobe assembled) may be formed at the pair of hollow protrusions 115 facingeach other with the bus bar 120 therebetween, e.g., at the wall bodies115 a of the pair of hollow protrusions 115 facing each other. In animplementation, the locking steps 115 p may be on the wall bodies 115 aof the hollow protrusions 115, and the bus bar 120, e.g., the protrudingconnection piece 120 c of the bus bar 120, may be inserted into thelocking steps 115 p (having a wedge shape). The bus bar 120 that isinserted into the locking steps 115 p and assembled may be effectivelyprevented from being separated from the battery cell 10. The pair oflocking steps 115 p may be formed at the pair of hollow protrusions 115facing each other with the bus bar 120 therebetween, may extend from thewall bodies 115 a of the hollow protrusions 115 to the protrudingconnection piece 120 c of the bus bar 120 to press the protrudingconnection piece 120 c toward the battery cell 10, and the couplingpieces 120 a at both ends of the bus bar 120 may be pressed toward theupper end portions 10 a or the lower end portions 10 b of the batterycells 10 through elastic deformation of the bent portions 120 bconnected to the protruding connection piece 120 c, accordingly the busbar 120 and the battery cells 10 may be firmly coupled to each other.

Referring to FIG. 9 , mold holes 110′ may be formed at positions in thecell holder 110 that correspond to the pair of locking steps 115 p. Inan implementation, the hollow protrusion 115 having the locking step 115p may protrude from the plate-shaped main body of the cell holder 110,and the mold hole 110′ may be formed at a position in the main body ofthe cell holder 110 that corresponds to the locking step 115 p, to passthrough the main body of the cell holder 110. The mold hole 110′ may beformed at a position in which an upper mold and a lower mold are coupledto each other when the cell holder 110 in which the locking steps 115 pare formed is molded, and a portion in which a molten resin is notfilled due to a coupling mechanism between the upper mold and the lowermold may remain as the mold hole 110′. In an implementation, the cellholder 110 having the locking steps 115 p therein may be easilyseparated from a mold in which the upper mold and the lower mold arecombined, and figures or structures of the locking steps 115 p of thecell holder 110 may be prevented from being damaged during theseparation.

Referring to FIG. 9 , the protruding connection piece 120 c of the busbar 120 may include position alignment holes 120 g for positionalignment with the cell holder 110. In an implementation, positionalignment pins 110 g (to be inserted into the position alignment holes120 g of the protruding connection piece 120 c) may be formed betweenthe pair of hollow protrusions 115. The protruding connection piece 120c having the position alignment holes 120 g may be placed on the mainbody of the cell holder 110 having the pair of hollow protrusions 115.In this case, the position alignment holes 120 g of the protrudingconnection piece 120 c may be inserted onto the position alignment pins110 g of the cell holder 110, and accordingly, the bus bar 120 may beassembled in a correct position on the cell holder 110. The pair ofposition alignment pins 110 g may be arranged along a direction in whichthe bus bar 120 extends. In this case, the direction in which the busbar 120 extends and the pair of position alignment pins 110 g arearranged, may intersect, e.g., may vertically intersect, a direction inwhich the pair of hollow protrusions 115 having the bus bar 120interposed therebetween face each other. In an implementation, theposition alignment holes 120 g and the position alignment pins 110 g maybe on the bus bar 120 and the cell holder 110 in which the bus bar 120is assembled, respectively. In an implementation, the position alignmentholes 120 g and the position alignment pins 110 g may be formed on thecell holder 110 and the bus bar 120, respectively, in a manner that theposition alignment holes 120 g and the position alignment pins 110 g areformed at positions corresponding to each other.

Referring to FIGS. 10 and 11 , the coupling pieces 120 a at both ends ofthe bus bar 120 may be exposed from or through the circuit board 130 onthe bus bars 120, e.g., may be exposed through the circuit board 130(e.g., the solid portion of the circuit board 130) through or at fillingholes FH of the circuit board 130. In an implementation, the fillinghole FH may expose at least a portion of the coupling piece 120 a of thebus bar 120. In an implementation, the coupling piece 120 a of the busbar 120 coupled to the upper end portion 10 a of the battery cell 10 maybe exposed through the filling hole FH of the circuit board 130, andpotting resin PR filling the filling hole FH may cover and protect acoupling portion or structure between the upper end portion 10 a of thebattery cell 10 and the coupling piece 120 a of the bus bar 120. In animplementation, the potting resin PR may protect the coupling structurebetween the battery cells 10 and the coupling piece 120 a of the busbars 20 from harmful elements such as oxygen or moisture, and mayprotect the coupling structure between different heterogeneous materialsformed by welding from galvanic corrosion. In an implementation, thefilling hole FH may be at or overlie the central portion of the upperend portion 10 a of each battery cell 10 to expose the bus bar 120(e.g., the coupling pieces 120 a at both ends of the bus bar 120)coupled to the central portion of the upper end portion 10 a of thebattery cell 10.

Referring to FIGS. 10 and 12 , the circuit board 130 may be on the busbars 120. The escape holes 132 a (exposing portions of the bus bars 120)may be in the circuit board 130. In an implementation, the escape hole132 a may entirely expose the central protruding connection piece 120 cof the bus bar 120. In an implementation, the escape hole 132 a mayentirely expose the protruding connection pieces 120 c, and the entireprotruding connection piece 120 c may be entirely exposed through thecircuit board 130 at the escape hole 132 a. In an implementation, theprotruding connection piece 120 c may not overlap the circuit board 130(e.g., the solid portion of the circuit board 130), e.g., may notoverlap the circuit board 130 (e.g., the solid portion of the circuitboard 130) at all, even at least partially.

Referring to FIG. 12 , the escape hole 132 a may accommodate theprotruding connection piece 120 c, and the protruding connection piece120 c may be at a location between a lower side 130 a and a upper side130 b of the circuit board 130 in the height direction (e.g., of thebattery cells 10). Here, the lower side 130 a of the circuit board 130may refer to a surface of the circuit board 130 that faces the batterycells 10 and the upper side 130 b of the circuit board 130 may refer toa surface opposite to the lower side 130 a. In an implementation, thecoupling pieces 120 a at both ends of the bus bar 120 may overlap (e.g.,underlie) the lower side 130 a of the circuit board 130 (e.g., the solidportion of the circuit board 130, such that the coupling pieces 120 aare between the battery cells 10 and the solid portion of the circuitboard 130). In an implementation, the protruding coupling piece 120 c(connected to the coupling pieces 120 a via the bent portions 120 b) maynot overlap the lower side 130 a of the circuit board 130 (e.g., thesolid portion of the circuit board 130), may be accommodated in theescape hole 132 a at a location between the lower side 130 a and theupper side 130 b of the circuit board 130 in the height direction, andthus may not form an additional thickness with respect to a thickness ofthe circuit board 130 in the height direction. In an implementation, aplane of the protruding coupling piece 120 c may be between a plane ofthe lower side 130 a and a plane of the upper side 130 b of the circuitboard 130 (e.g., in the height direction of the battery cells 10)

The protruding connection piece 120 c of the bus bar 120 and the circuitboard 130 (e.g., the solid portion of the circuit board 130) may notoverlap each other due to the escape holes 132 a, the circuit board 130may be arranged at a low position, e.g., closer to the battery cell 10,a distance q between the circuit board 130 and the battery cell 10 inthe height direction may be reduced, and a length of a connection member125 that forms a voltage measurement line between the circuit board 130and the battery cell 10 may be reduced. In an implementation, firmjunctions may be formed at the circuit board 130 and the battery cell 10by wire bonding or ribbon bonding that bonds, by ultrasonic welding, oneend portion and the other end portion of the connection member 125 tothe circuit board 130 and the battery cell 10, respectively, and weldingdefects of the ultrasonic welding due to relative vibrations between thecircuit board 130 and the battery cell 10 may be prevented.

In an implementation, the protruding connection piece 120 c of the busbar 120 and the circuit board 130 (e.g., the solid portion of thecircuit board 130) may not overlap each other in the height directiondue to the escape holes 132 a, the circuit board 130 may be arranged atthe low position (close to the battery cell 10), the height of theentire battery pack may be reduced, and a thinner battery pack may beprovided.

Referring to FIG. 10 , the bus bar 120 may extend between the pair ofhollow protrusions 115, and the protruding connection piece 120 c of thebus bar 120 may be between the pair of hollow protrusions 115. In animplementation, the escape hole 132 a may be at a position in thecircuit board 130 corresponding to the protruding connection piece 120c, e.g., at a position between the pair of hollow protrusions 115. Theescape hole 132 a may be a portion of or continuous with a bus openingregion 132 b that exposes the pair of hollow protrusions 115 that faceeach other with the bus bar 120 therebetween and a pair of cooling flowpaths F as well as the protruding connection pieces 120 c of the bus bar120. In an implementation, the circuit board 130 may include the busopening region 132 b connected to the escape hole 132 a that exposes theprotruding connection piece 120 c of the bus bar 120, to be formed in asingle hole shape, for exposing the hollow protrusions 115 and theprotruding connection piece 120 c of the bus bar 120 together.

The bus opening region 132 b may have the single hole shape in thecircuit board 130 to expose a portion of the bus bar 120, e.g., theprotruding connection piece 120 c of the bus bar 120, together with thepair of hollow protrusions 115 (or the pair of cooling flow paths F)facing each other with the bus bar 120 therebetween. In this case, theescape hole 132 a that entirely exposes the protruding connection piece120 c of the bus bar 120 may refer to a region or part of the busopening region 132 b having the single hole shape, excluding a regionthrough which the hollow protrusions 115 pass.

If one hole for exposing the protruding connection piece 120 c of thebus bar 120 and two holes for exposing the cooling flow paths F adjacentto each other were to be separately formed with narrow portionstherebetween, e.g., if three holes were to be separately formed withnarrow portions therebetween, the circuit board 130 could be easilydamaged. In an implementation, the protruding connection piece 120 c ofthe bus bar 120 and the pair of cooling flow paths F adjacent to eachother may be exposed through the bus opening region 132 b having thesingle hole shape, and accordingly, a structure of the circuit board 130may be simplified and a risk of damage due to insufficient rigidity ofthe circuit board 130 may be reduced.

The bus opening region 132 b may expose the pair of cooling flow paths F(or the hollow protrusions 115) facing each other with the bus bar 120therebetween. As will be described below, the bus opening region 132 bmay have the single hole shape together with a connection opening region132 c that exposes a pair of cooling flow paths F (or the hollowprotrusions 115) facing each other with the connection member 125therebetween, and the bus opening region 132 b and the connectionopening region 132 c may form a second opening region 132 having asingle hole shape. In an implementation, the cooling flow paths F (orthe hollow protrusions 115) exposed through the second opening region132 may include the pair of cooling flow paths F (or first and secondhollow protrusions 1151 and 1152) facing each other with the bus bar 120therebetween, and the pair of cooling flow paths F (or the first andthird hollow protrusions 1151 and 1153) facing each other with theconnection member 125 therebetween, and may include a total of threecooling flow paths F including the cooling flow path F (or the firsthollow protrusion 1151) arranged between the bus bar 120 and theconnection member 125. In an implementation, the hollow protrusions 115exposed through the second opening region 132 may include the threehollow protrusions 115 including the first hollow protrusion 1151between the bus bar 120 and the connection member 125, the second hollowprotrusion 1152 facing the first hollow protrusion 1151 with the bus bar120 therebetween, and the third hollow protrusion 1153 facing the firsthollow protrusion 1151 with the connection member 125 therebetween.

In an implementation, the escape hole 132 a that exposes the protrudingconnection piece 120 c of the bus bar 120 may be a portion of the secondopening region 132, the protruding connection piece 120 c of the bus bar120 may be exposed through the second opening region 132, and theprotruding connection pieces 120 c may be entirely exposed through thecircuit board 130 at the second opening region 132.

Referring to FIG. 10 , the circuit board 130 may include the openregions 135 having a hole shape through which the cooling flow paths F(or the hollow protrusion 115) pass. The cooling flow path F may passthrough the open region 135 of the circuit board 130 and may extendacross the circuit board 130, e.g., the hollow protrusion 115 of thecell holder 110 may be inserted into the open region 135 of the circuitboard 130 to form the cooling flow path F that passes through the openregion 135 of the circuit board 130. To this end, the open regions 135of the circuit board 130 may be at positions corresponding to the hollowprotrusions 115 of the cell holder 110 and may have a shapecorresponding to the hollow protrusion 115 of the cell holder 110. In animplementation, the open region 135 (e.g. a first opening region 131) ofthe circuit board 130 may have a circular shape corresponding to thehollow protrusion 115 including the circular wall body 115 a. In animplementation, the open region 135 (e.g., the first opening region 131)of the circuit board 130 may be formed in various shapes correspondingto the hollow protrusion 115, e.g., in an elliptical shape or ahexagonal shape.

As will be described below, the first opening region 131 of the openregion 135 may surround the outer circumference of some of the hollowprotrusions 115, and the second opening region 132 may surround at leasta portion of the outer circumference of other ones of the hollowprotrusions 115. In an implementation, the second opening region 132 mayexpose two or more hollow protrusions 115 adjacent to each othertogether, and may surround at least a portion of the outer circumferenceof each of the two or more hollow protrusions 115 together.

The open region 135 of the circuit board 130 may include the firstopening regions 131 each formed for each cooling flow path F (or thehollow protrusion 115) individually and the second opening regions 132each formed in common for two or more cooling flow paths F adjacent toeach other. In an implementation, the second opening region 132 mayinclude the connection opening region 132 c and the bus opening region132 b. The connection opening region 132 c may be formed in common forthe pair of cooling flow paths F facing each other with the connectionmember 125 therebetween. The connection member 125 will be described inmore detail below. The bus opening region 132 b may be formed in commonfor the pair of cooling flow paths F facing each other with the bus bar120 interposed therebetween. In an implementation, the connectionopening region 132 c and the bus opening region 132 b may not beindependent holes separated from each other, and may be rather connectedto (e.g., continuous with) each other to form the second opening region132 in a single hole configuration. The number of cooling flow paths Fin the pair of cooling flow paths F exposed through the connectionopening region 132 c and the pair of cooling flow paths F exposedthrough the bus opening region 132 b may be 3 rather than 4 as one ofthe cooling flow paths F is included in both pairs. In animplementation, the cooling flow path F at a position where theconnection opening region 132 c and the bus opening region 132 b overlapor meet each other, e.g., the cooling flow path F (or the first hollowprotrusion 1151) between the connection member 125 and the bus bar 120may be included in both the pair of cooling flow paths F (or the firstand second hollow protrusions 1151 and 1152) exposed through the busopening region 132 b and the pair of cooling flow paths F (or the firstand third hollow protrusions 1151 and 1153) exposed through theconnection opening region 132 c. In an implementation, the hollowprotrusions 115 (or the cooling flow paths F) exposed through the secondopening region 132 may include a total of three hollow protrusions 115,e.g., the first hollow protrusion 1151 between the bus bar 120 and theconnection member 125, the second hollow protrusion 1152 facing thefirst hollow protrusion 1151 with the bus bar 120 therebetween, and thethird hollow protrusion 1153 facing the first hollow protrusion with theconnection member 125 therebetween.

Each of the first opening regions 131 may be a hole formed for each ofthe cooling flow paths F individually, and may expose the cooling flowpath F through the circuit board 130. Unlike the first opening region131, the second opening region 132 may have a single hole shape incommon for two or more cooling flow paths F adjacent to each other, andmay expose the two or more neighboring cooling flow paths F togetherfrom the circuit board 130.

The connection opening region 132 c of the second opening region 132 mayexpose a portion of the upper end portions 10 a of the battery cells 10together with the pair of cooling flow paths F adjacent to each other(e.g., the pair of cooling flow paths F facing each other with theconnection member 125 therebetween). In an implementation, theconnection members 125 may be connected to the upper end portions 10 aof the battery cells 10 exposed through the connection opening region132 c. In an implementation, the connection opening region 132 c mayexpose a portion of the upper end portions 10 a of the battery cells 10together with the pair of adjacent cooling flow paths F. In the casewhere the connection opening region 132 c exposes the portion of theupper end portions 10 a of the battery cells 10, one end of theconnection member 125 may be connected to the upper end portion 10 a ofthe battery cell 10 exposed from the circuit board 130 through theconnection opening region 132 c, and the other end of the connectionmember 125 may be connected to the circuit board 130, thus the voltagemeasurement line may be formed between the battery cell 10 and thecircuit board 130, and the connection opening region 132 c may include aconnection hole CH for allowing the connection members 125 to passthrough the circuit board 130 and be connected. The connection hole CHwill be described in more detail below.

Referring to FIG. 10 , according to an embodiment, the connectionopening region 132 c of the second opening region 132 may exposeportions of the upper end portions 10 a of the battery cells 10 togetherwith the pair of cooling flow paths F adjacent to each other (e.g., thepair of cooling flow paths F facing each other with the connectionmember 125), and may function as the connection hole CH. In animplementation, the connection opening region 132 c and the connectionhole CH may have substantially the same configuration, e.g., the samehole formed in the circuit board 130. In the present specification, forconvenience of understanding, the connection opening region 132 c andthe connection hole CH will be assigned different reference numerals.

Portions of the upper end portions 10 a of the battery cells 10 may beexposed through the connection hole CH (or the connection opening region132 c), and the connection member 125 may be connected to the upper endportion 10 a of the battery cell 10 exposed through the circuit board130. In an implementation, the connection member 125 may include aconductive wire or a conductive ribbon having one end connected to theupper end portion 10 a of the battery cell 10 and the other endconnected to the circuit board 130, and the connection member 125 may beformed by wire bonding that bonds the one end and the other end of theconductive wire to the upper end portion 10 a of the battery cell 10 andthe circuit board 130, respectively, or ribbon bonding that bonds theone end and the other end of the conductive ribbon to the upper endportion 10 a of the battery cell 10 and the circuit board 130,respectively. In this case, in the wire bonding or the ribbon bonding,the conductive wire or the conductive ribbon may be bonded to the upperend portion 10 a of the battery cell 10 and the circuit board 130 byultrasonic welding.

In an implementation, the connection member 125 may be a pair ofconductive wires that extend in parallel to connect the battery cell 10to the circuit board 130, and may firmly connect the battery cell 10 tothe circuit board 130 by preparing for a situation where one of theconductive wires is disconnected due to insufficient mechanicalstrength. In the case where the connection member 125 is the conductiveribbon that has a mechanical strength greater than that of theconductive wire, the battery cell 10 and the circuit board 130 may beelectrically connected to each other through a single conductive ribbon.For reference, the connection member 125 exemplarily illustrated in FIG.10 may be the conductive ribbon.

The connection hole CH may be formed in a region of the circuit board130 that overlaps the pair of battery cells 10 adjacent to each other toexpose the upper end portions 10 a of the pair of adjacent battery cells10 together. In an implementation, the connection hole CH may be formedin a region of the circuit board 130 that overlaps a portion of the pairof adjacent battery cells 10, e.g., may be formed in a region thatoverlaps edge portions of the pair of battery cells 10. In addition, twoconnection members 125 may be connected to the edge portions of the pairof battery cells 10 adjacent to each other exposed through theconnection hole CH.

The edge portions of the upper end portions 10 a of the pair of batterycells 10 exposed through the connection hole CH may form the firstelectrodes 11 having the same polarity. In an implementation, the pairof adjacent battery cells 10 exposed by the same connection hole CH maybe arranged in a pattern in which one of the pair of adjacent batterycells 10 is inverted in the height direction of the battery cells 10,however, the edge portions of the upper end portions 10 a of the pair ofadjacent battery cells 10 may form the first electrodes 11 having thesame polarity regardless of the vertical arrangement of the batterycells 10. As illustrated in FIG. 3 , the can N forming the firstelectrode 11 may extend from the edge portion of the upper end portion10 a to the entire lower end portion 10 b, thus, regardless of thevertical arrangement of the battery cells 10, both the edge portions ofthe upper end portions 10 a and the edge portions of the lower endportions 10 b of the adjacent battery cells 10 may form the firstelectrodes 11 having the same polarity.

As described above, the connection members 125 may be connected to theedge portions of the upper end portions 10 a of the battery cells 10exposed through the connection hole CH and may be connected to the firstelectrodes 11 of the battery cells 10. Referring to FIG. 2 , most of aplurality of connection members 125 may be connected to the firstelectrodes 11 of the battery cells 10 exposed through the connectionholes CH, some of the connection members 125 may be connected to thefirst and second output terminals 121 and 122 or to the battery cells 10connected to the first and second output terminals 121 and 122, and thusmay be connected to the second electrodes 12 of the battery cells 10. Inan implementation, the first and second output terminals 121 and 122 maybe connected to the low-potential battery cell 10 having the lowestpotential and the high-potential battery cell 10 having the highestpotential, respectively, in a group of the battery cells 10 electricallyconnected to each other. In this case, one connection member 125 a maybe connected to the first electrode 11 at the upper end portion 10 a ofthe low-potential battery cell 10, and the other connection member 125 bmay be connected to the second electrode 12 at the upper end portion 10a of the high-potential battery cell 10. In an implementation, among agroup of the connection members 125 that constitutes the battery pack,the one connection member 125 a may be connected to the first electrode11 in the low-potential battery cell 10 connected to the first outputterminal 121, while the other connection member 125 b may be connectedto the second electrode 12 in the high-potential battery cell 10connected to the second output terminal 122, and the remainingconnection members 125 may be connected to the first electrodes 11 atthe edge portions of the upper end portions 10 a of the battery cells 10having middle potentials other than the low-potential battery cell 10and the high-potential battery cell 10. In an implementation, theconnection members 125 may be connected to the second electrode 12 onlyfor the high-potential battery cell 10 connected to the second outputterminal 122, and may be connected to the first electrodes 11 for theremaining battery cells 10.

Referring to FIG. 10 , the connection opening region 132 c (or theconnection hole CH) may have a sufficient area to expose the pair ofcooling flow paths F adjacent to each other (e.g., the pair of coolingflow paths F facing each other with the connection member 125therebetween), together with the edge portions of the pair of batterycells adjacent to each other 10. In an implementation, a direction inwhich the pair of battery cells 10 exposed through the connectionopening region 132 c face each other and a direction in which the pairof cooling flow paths F (e.g., the pair of cooling flow paths F facingeach other with the connection member 125 therebetween) exposed throughthe connection opening region 132 c may intersect each other, e.g., mayvertically intersect each other.

If one connection hole CH for exposing the edge portions of the pair ofbattery cells 10 adjacent to each other and two open regions 135 forexposing the cooling flow paths F adjacent to each other were to beseparately formed with narrow portions therebetween, e.g., if threeholes were separately formed with narrow portions therebetween, thecircuit board 130 could be easily damaged. In an implementation, theconnection hole CH or the connection opening region 132 c having asingle hole shape may expose the edge portions of the pair of batterycells 10 adjacent to each other and the pair of cooling flow paths Fadjacent to each other, and accordingly, the structure of the circuitboard 130 may be simplified and a risk of damage due to insufficientrigidity of the circuit board 130 may be reduced.

The connections members 125 may be between the circuit board 130 and theupper end portions 10 a of the battery cells 10 exposed through theconnection opening region 132 c or the connection hole CH, toelectrically connect the circuit board 130 to the upper end portions 10a of the battery cells 10, and the connection member 125 may transmitvoltage information of the battery cell 10 to the circuit board 130. Inan implementation, the connection member 125 may electrically connectthe upper end portion 10 a of the battery cell 10 to a connection pad133 of the circuit board 130. The connection pads 133 of the circuitboard 130 may be formed around the connection hole CH, e.g., a pair ofconnection pads 133 each electrically connected to each of the pair ofadjacent battery cells 10 may be formed at positions facing each otheraround the connection hole CH.

In an implementation, the connection opening region 132 c may form thesecond opening region 132 together with the bus opening region 132 bthat exposes the pair of cooling flow paths F facing each other with thebus bar 120 therebetween. In this case, the second opening region 132may have a single hole shape, and may extend along an outercircumferential direction surrounding the filling hole FH. The secondopening region 132 may include the cooling flow path F (or the firsthollow protrusion 1151) between the bus bar 120 and the connectionmember 125, another cooling flow path F (or the second hollow protrusion1152) arranged with the cooling flow path F (or the first hollowprotrusion 1151) with the bus bar 120 therebetween, and yet anothercooling flow path F (or the third hollow protrusion 1153) arranged withthe cooling flow path F (or the first hollow protrusion 1151) and theconnection member 125 therebetween, and may expose together the threedifferent cooling flow paths F continuously arranged along the outercircumferential direction surrounding the filling hole FH. In animplementation, as illustrated in FIG. 4 , six cooling flow paths F maybe formed along the outer circumferential direction of one battery cell10, and three adjacent cooling flow paths F among the six cooling flowpaths F may be exposed through the second opening region 132.

Referring to FIG. 10 , the second opening region 132 may include thefirst hollow protrusion 1151 between the bus bar 120 and the connectionmember 125, the second hollow protrusion 1152 facing the first hollowprotrusion 1151 with the bus bar 120 therebetween, and the third hollowprotrusion 1153 facing the first hollow protrusion 1151 with theconnection member 125 therebetween, and overall may expose threedifferent hollow protrusions 115 continuously arranged along the outercircumferential direction surrounding the filling hole FH.

Referring to FIG. 10 , a thermistor TH for measuring a temperature ofthe battery cell 10 may be arranged at the upper end portion 10 a of thebattery cell 10, e.g., the thermistor TH may be arranged at the edgeportion of the battery cell 10. In an implementation, the thermistor THmay be at a portion of the edge portion of the battery cell 10 that isspaced apart from, in the outer circumferential direction of the batterycell 10, the portion of the edge portion of the battery cell 10 to whichthe connection member 125 is connected. In an implementation, theconnection member 125 and the thermistor TH may be arranged at positionsspaced apart from each other along the edge portion of the battery cell10 to avoid interference with each other. In an implementation, thethermistor TH may be a chip-type thermistor TH that may be directlybonded to the edge portion of the battery cell 10. In addition, thethermistor TH may be bonded to the edge portion of the battery cell 10by solder mounting.

In the cell holder 110 in which the battery cells 10 are assembled, along hole may be formed to expose the edge portions of the battery cells10 while extending in the outer circumferential direction of the batterycells 10, and the connection members 125 and the thermistors TH may bearranged at positions spaced apart from each other in the edge portionsof the battery cells 10 while the edge portions of the battery cells 10is exposed through the long hole formed in the cell holder 110. Asillustrated in FIG. 11 , the adhesive resin AR may be formed on theconnection member 125 bonded to the edge portion of the battery cell 10,and the adhesive resin AR may not extend to the position of thethermistor TH and may not be formed on the thermistor TH.

Referring to FIG. 13 , the connection hole CH may be formed in analternate pattern along the column direction (e.g., L1 and L2) of thebattery cells 10 (or the filling hole FH) to expose the pair of batterycells 10 adjacent to each other along the column direction (for example,L1 and L2) of the battery cells 10 (or the filling hole FH). In animplementation, the first and second opening regions 131 and 132 forexposing the cooling flow paths F may formed at the circuit board 130,and the connection opening region 132 c (or the second opening region132) that functions as the connection hole CH and the first openingregion 131 that does not function as the connection hole CH may bearranged in an alternate pattern along the column direction (e.g., L1and L2) of the battery cells 10 (or the filling hole FH). In animplementation, one connection opening region 132 c (or the secondopening region 132) that functions as the connection hole CH may beformed between two battery cells 10 (or the filling holes FH) that arepaired with each other along the column direction (e.g., L1 and L2), andthe connection opening region 132 c (or the second opening region 132)that functions as the connection hole CH may not be formed between twobattery cells 10 (or the filling holes FH) that are not paired with eachother. In other words, the connection opening region 132 c (or thesecond opening regions 132) may not be formed between every two batterycells 10 (or the filling holes FH) adjacent to each other along thecolumn direction (e.g., L1 or L2) of the battery cell 10 or the fillinghole FH, but may be formed alternatively between two battery cells 10(or the filling holes FH) adjacent to each other along the columndirection (e.g., L1 or L2) of the battery cell 10 (or the filling holeFH). In this case, the first opening region 131 for exposing the coolingflow path F passing between the adjacent battery cells 10 may be formedat a position P, between the adjacent battery cells 10 or between theadjacent filling holes FH, where the connection opening region 132 (orthe second opening region 132) is not formed or a position adjacentthereto.

As will be described below, the filling hole FH may be formed at aposition overlying the central position of the upper end portion 10 a ofthe battery cell 10, and in the case where the first and second openingregions 131 and 132 may be arranged between the adjacent battery cells10 in an alternating pattern along the column direction Z1 of thebattery cell 10, the first and second opening regions 131 and 132 may bearranged between the adjacent filling holes FH in the alternatingpattern along the column direction (e.g., L1 and L2) of the fillingholes FH, and may be arranged at positions adjacent to the position Pbetween the adjacent filling holes FH in the alternating pattern. In animplementation, the first opening region 131 may be formed at a positionadjacent to the position P between the adjacent filling holes FH ratherthan between the adjacent filling holes FH in the column direction(e.g., L1 and L2) of the filling holes FH, and even in this case, thefirst open region 131 may still be arranged between the adjacent batterycells 10. This is because the filling hole FH is formed at the centralportion of the adjacent battery cell 10.

As described above with reference to FIG. 4 , six cooling flow paths Fmay be formed along the circumferential direction of one battery cell10. In this case, four cooling flow paths F may be formed at both sidesof one battery cell 10 in the column direction Z1 of the battery cells10, and at least one cooling flow path F of two adjacent cooling flowpaths F formed at one side of the battery cell 10 may be exposed by thefirst opening region 131 formed in each cooling flow path F, and twoadjacent cooling flow paths F formed at the other side of the batterycell 10 may be exposed by the connection opening region 132 c or thesecond opening region 132 formed in common with respect to the twocooling flow paths F. As described above, with respect to one batterycell 10, the first opening region 131 may be formed at one side, theconnection opening region 132 c (or the second opening region 132) maybe formed at the other side, and the first and second opening regions131 and 132 may be arranged in an alternating pattern along the columndirections (for example, L1 and L2) of the battery cell 10 (or thefilling hole FH). In an implementation, the connection opening region132 c (or the second opening region 132) that functions as theconnection hole CH and the first opening region 131 that does notfunction as the connection hole CH are arranged in an alternate patternalong the column direction (e.g., L1 and L2) of the battery cells 10 (orthe filling hole FH).

Referring to FIG. 13 , the second opening regions 132 that extend alongthe outer circumferential direction of the filling holes FH of theadjacent rows (e.g., L1 and L2) may be formed in different shapes, e.g.,the second opening region 132 that extends along the outercircumferential direction of the filling hole FH of the first row L1 mayextend along the outer circumferential direction of the filling holes FHin a downward direction from the connection member 125 toward thefilling holes FH of the second row L2. In an implementation, the secondopening region 132 that extends along the outer circumferentialdirection of the filling hole FH of the second row L2 may extend fromthe connection member 125 toward the filling hole FH of the first row L1along the outer circumferential direction of the filling hole FH in theupper direction. As described above, the second opening regions 132 thatextends along the outer circumferential direction of the filling hole FHin the first and second rows L1 and L2 adjacent to each other may beformed to have different extension directions from each other, and thus,the second opening regions 132 having the different extension directionsfrom each other may be densely arranged in a narrow space between thefilling holes FH in the first and second rows L1 and L2 while avoidinginterference between each other. In an implementation, the secondopening region 132 may extend along the outer circumferential directionof the filling hole FH. In an implementation, the filling hole FH may beomitted and in this case, the second opening region 132 may beunderstood as extending along the outer circumferential direction of thecentral portion of the upper end portion 10 a of the battery cell 10.This is because the filling hole FH may be formed at the central portionof the upper end portion 10 a of each battery cell 10 to expose the busbar 120 coupled to the central portion of the upper end portion 10 a ofthe battery cell 10.

In an implementation, referring to FIG. 1 , the circuit board 130 may beon the upper holder 110 a and may not be arranged under the lower holder110 b. In an implementation, the circuit board 130 may be selectivelyarranged on any one of the upper holder 110 a and the lower holder 110b, e.g., the circuit board 130 may be arranged on the upper holder 110 aand may collect voltage information of the plurality of battery cells 10through the upper end portions 10 a of the battery cells 10. In animplementation, the circuit board 130 may collect the voltageinformation of the plurality of battery cells 10 through the upper endportions 10 a or the lower end portions 10 b of the plurality of batterycells 10, and for example, the circuit board 130 may collect the voltageinformation of the plurality of battery cells 10 through the upper endportions 10 a of the plurality of battery cells 10. In animplementation, the battery cell 10 may include the first and secondelectrodes 11 and 12 that are formed at the upper end portion 10 a andthe lower end portion 10 b, the circuit board 130 may not need to beconnected to both of the upper end portion 10 a and the lower endportion 10 b of the battery cell 10 to obtain the voltage information ofthe battery cell 10, the voltage information of the plurality of batterycells 10 may be obtained through the upper end portions 10 a or thelower end portions 10 b of the battery cells 10, e.g., the upper endportions 10 a of the battery cells 10, and the voltage information ofthe battery cells 10 may be collected through the circuit board 130 thatis selectively arranged on the upper end portions 10 a of the batterycells 10, thus the structure of the entire battery pack may besimplified. In an implementation, the electrical connection of thebattery cell 10 may be performed through both of the upper end portion10 a and the lower end portion 10 b of the battery cell 10, and thevoltage measurement of the battery cell 10 may be performed through anyone of the upper end portion 10 a of the battery cell 10 selectively,for example, through the upper end portion 10 a of the battery cell 10.

If the voltage measurement were to be performed on both of the upper endportion 10 a and the lower end portion 10 b of the battery cell 10, thecircuit board 130 may need to be arranged on both of the upper endportion 10 a and the lower end portion 10 b of the battery cell 10, andaccordingly, the overall structure of the battery pack may becomplicated, and a separate wiring structure for connecting the circuitboards 130 on both sides may be required to collect the voltageinformation measured from the circuit boards 130 on both sides.

Referring to FIGS. 9 and 11 , according to an embodiment, the pottingresin PR may be formed at a position corresponding to the centralportion of the upper end portion 10 a or the lower end portion 10 b ofthe battery cell 10, and the adhesive resin AR may be formed at aposition corresponding to the edge portion surrounding the centralportion of the upper end portion 10 a or the lower end portion 10 b ofthe battery cell 10. In this case, the potting resin PR and the adhesiveresin AR may include different components.

In an implementation, the bus bar 120 that electrically connects theadjacent battery cells 10 to each other may connect the central portionsof the upper end portions 10 a of the adjacent battery cells 10 to eachother. In this case, the potting resin PR may be formed on the couplingportions between the central portions of the upper end portions 10 a ofthe battery cells 10 and the coupling pieces 120 a at both ends of thebus bar 120, and according to an embodiment, the potting resin PR may beinjected onto the coupling pieces 120 a at both ends of the bus bar 120through the filling hole FH of the circuit board 130.

The potting resin PR may help protect the coupling structure between thebattery cells 10 and the coupling pieces 120 a of the bus bar 120 fromharmful elements such as oxygen or moisture, and may help protect thecoupling structure between different heterogeneous materials formed bywelding, e.g., the heterogeneous materials formed between the upper endportion 10 a of the battery cells 10 and the coupling piece 120 a of thebus bar 120 from galvanic corrosion.

The potting resin PR may be filled in the filling hole FH of the circuitboard 130 on the bus bars 120, and the filling holes FH of the circuitboard 130 may expose the coupling pieces 120 a at both ends of the busbar 120 connected to the battery cells 10, respectively. In animplementation, the filling hole FH may be formed for each of thebattery cells 10, two filling holes FH may be formed for each of the busbars 120 that connects two adjacent battery cells 10 to each other,e.g., one filling hole FH may be formed for each of the coupling pieces120 a at both ends of the bus bar 120, the potting resin PR may befilled in each of the filling holes FH, and thus the potting resin PRfilled in the filling holes FH may cover the coupling portions betweenthe battery cells 10 and the coupling pieces 120 a formed at both endsof the bus bars 120 (e.g., the coupling pieces 120 a formed at both endsof the bus bar 120). For example, the potting resin PR being filling thefilling holes FH of the circuit board 130 may be injected onto thecoupling pieces 120 a of the bus bars 120 interposed between the circuitboard 130 and the battery cells 10.

In an implementation, the bus bar 120 may include the central protrudingconnection piece 120 c that connects the coupling pieces 120 a at bothends to each other, and the bent portions 120 b that connect thecoupling pieces 120 a at both ends to the central protruding connectionpiece 120 c in a bent shape and support the protruding connection piece120 c at a level spaced apart from the battery cells 10 from thecoupling pieces 120 a at both ends in the height direction of thebattery cells 10. In this case, the circuit board 130 arranged on thebus bar 120 may have the escape hole 132 a for completely exposing theentire protruding connection piece 120 c. As illustrated in FIG. 12 ,the protruding connection piece 120 c of the bus bar 120 and the circuitboard 130 (the solid portion of the circuit board 130) may be arrangedso as not to overlap each other in the height direction through theescape hole 132 a formed in the circuit board 130, thus the circuitboard 130 may be arranged at a position close to the coupling pieces 120a of the bus bar 120, and the gap q between the circuit board 130 andthe coupling piece 120 a of the bus bar 120 in the height direction maybe reduced, such that the amount of the potting resin PR injected ontothe coupling pieces 120 a of the bus bars 120 through the filling holesFH of the circuit board 130 may be reduced, and the contamination of thesurroundings due to the movement of the surplus or uncontrollablepotting resin PR may be prevented.

The potting resin PR may be injected onto the coupling pieces 120 a atboth ends of the bus bar 120 based on proper fluidity when uncured,e.g., may be injected through the filling hole FH of the circuit board130, may be cured, after injection, by irradiating UV light, heating, orcuring in a timely manner, and then may protect the coupling portionsbetween the bus bars 120 and the battery cells 10 from external harmfulelements such as oxygen or moisture. In addition, the potting resin PRmay insulate the upper end portion 10 a of the battery cell 10 exposedthrough the filling hole FH of the circuit board 130, from the bus bar120. In an implementation, the PR may include a urethane resin such aspolyurethane.

In an implementation, as illustrated in FIG. 11 , the potting resin PRmay be on the coupling structures between the upper end portions 10 a ofthe battery cells 10 and the bus bars 120, or the potting resin PR mayalso be formed on the coupling structures between the lower end portions10 b of the battery cells 10 and the bus bars 120. In an implementation,the circuit board 130 may be selectively formed only on the upper endportion 10 a of the battery cell 10 (i.e., the circuit board 130 may beselectively arranged only on the upper holder 110 a), and in this case,the coupling portion between the lower end portion 10 b of the batterycell 10 and the bus bar 120 may be formed directly on the couplingportion between the lower end portion 10 b of the battery cell 10 andthe bus bar 120 without the filling hole FH of the circuit board 130.

Throughout the present specification, in the case where the pottingresin PR is formed at a position corresponding to the central portion ofthe upper end portion 10 a or the lower end portion 10 b of the batterycell 10 in the height direction of the battery cell 10, the pottingresin PR may be formed on the coupling structure between the batterycell 10 and the bus bar 120 to cover the coupling portion, and thepotting resin PR may be filled in the filling hole FH of the circuitboard 130 formed on the bus bar 120.

In the case where the potting resin PR is formed on the central portionof the upper end portion 10 a or the lower end portion 10 b of thebattery cell 10, the potting resin PR may be formed at the centralportion of the upper end portion 10 a or the lower end portion 10 b ofthe battery cell 10, to which the coupling pieces 120 a at both ends ofthe bus bar 120 are coupled. Here, the central portion of the upper endportion 10 a or the lower end portion 10 b of the battery cell 10 refersto a position to which the coupling pieces 120 a at both ends of the busbar 120 are coupled, e.g., the upper end portion 10 a or the lower endportion 10 b of the battery cell 10, and the central position of theupper end portion 10 a or the lower end portion 10 b of the battery cell10 is not limited thereto. In an implementation, in relation to theposition where the potting resin PR is formed, the central portion ofthe upper end portion 10 a or the lower end portion 10 b of the batterycell 10 may refer to an inner area of the upper end portion 10 a or thelower end portion 10 b of the battery cell 10, other than the edgeportion, e.g., an inner area surrounded by the edge portion, todistinguish a position where any one of the first and second electrodes11 and 12 of the battery cell 10 is formed from a position where anotherelectrode is formed, along the upper end portion 10 a or the lower endportion 10 b of the battery cell 10, and in relation to the positionwhere the potting resin PR is formed, the central portion of the upperend portion 10 a or the lower end portion 10 b of the battery cell 10may refer to an inner area of the upper end portion 10 a or the lowerend portion 10 b of the battery cell 10, based on the boundary betweenthe one electrode and another of the battery cell 10. As described abovewith reference to FIG. 3 , the second electrode 12 of the battery cell10 may be formed at the central portion of the upper end portion 10 a ofthe battery cell 10, and the first electrode 11 may be formed at theedge portion of the upper end portion 10 a. In this case, in relation tothe positions to which the coupling pieces 120 a at both ends of the busbar 120 are coupled, the central portion of the upper end portion 10 aof the battery cell 10 may refer to the second electrode 12 formed atthe central portion of the upper end portion 10 a of the battery cell10.

Referring to FIGS. 9 and 10 , the upper end portion 10 a of the batterycell 10 may be exposed through the terminal hole 112 of the upper holder110 a in which the battery cells 10 are assembled, and the upper endportion 10 a of the battery cell 10 exposed through the terminal hole112 of the upper holder 110 a may be coupled to the bus bar 120 on theupper holder 110 a. In this case, the terminal hole 112 of the upperholder 110 a and the filling hole FH of the circuit board 130 may beformed at positions corresponding to (e.g., aligned with or overlying)each other in the height direction of the battery cells 10. The terminalhole 112 of the upper holder 110 a is to expose the upper end portion 10a of the battery cell 10, the filling hole FH of the circuit board 130is to expose the coupling piece 120 a of the bus bar 120 coupled to theupper end portion 10 a of the battery cell 10, and thus the terminalhole 112 of the upper holder 110 a and the filling hole FH of thecircuit board 130 may be aligned at positions corresponding to eachother in the height direction of the battery cell 10. In animplementation, in the case where the circuit board 130 is arrangedunder the lower holder 110 b, the terminal hole 112 of the lower holder110 b and the filling hole FH of the circuit board 130 may be aligned atpositions corresponding to each other.

Referring to FIGS. 10 and 11 , according to an embodiment, theconnection member 125 forming the voltage measurement line between thebattery cell 10 and the circuit board 130 may be coupled to the edgeportion of the upper end portion 10 a of the battery cell 10. Here, theedge portion of the upper end portion 10 a of the battery cell 10 mayrefer to the portion surrounding the central portion of the upper endportion 10 a. The connection member 125 may pass through the connectionhole CH of the circuit board 130 to electrically connect the batterycell 10 to the circuit board 130, and one end of the connection member125 may form a junction with the edge portion of the battery cell 10 andthe other end of the connection member 125 may form a junction with thecircuit board 130. In this case, the adhesive resin AR may cover thejunctions of one end and the other end of the connection member 125,e.g., the adhesive resin AR may continuously cover the junctions of oneend and the other end of the connection member 125 together. Here, theadhesive resin AR may entirely cover the connection member 125. Theadhesive resin AR may cover the edge portion of the upper end portion 10a of the battery cell 10 and the junctions of the connection member 125formed on the circuit board 130 to protect the junctions from anexternal impact, and the adhesive resin AR may entirely cover theconnection member 125 to prevent the connection member 125 formed of theconductive wire or the conductive ribbon from being disconnected due toan insufficient mechanical strength.

The adhesive resin AR may cover two connection members 125 bonded to theedge portions of two adjacent battery cells 10 exposed through theconnection hole CH. In an implementation, the adhesive resin AR maycover one ends and other ends of the two connection members 125respectively bonded to the two battery cells 10 exposed through theconnection hole CH, and may continuously cover the one ends and theother ends of the two connection members 125. In this case, the adhesiveresin AR may entirely cover the two connection members 125 bonded to thetwo battery cells 10 exposed through the connection hole CH. Theadhesive resin AR may continuously cover the upper end portions 10 a ofthe two battery cells 10 exposed through the connection hole CH whileentirely covering the two connection members 125, and may electricallyinsulate the upper end portions 10 a of the two battery cells 10 exposedthrough the connection hole CH. For example, the adhesive resin AR maycover the upper end portions 10 a of the two battery cells 10 exposedthrough the connection hole CH together with the connection members 125,thereby electrically insulating the two connection members 125 and theupper end portions 10 a of the two battery cells 10.

The connection member 125 may be supported while being suspended betweenthe one end bonded to the edge portion of the upper end portion 10 a ofthe battery cell 10 and the other end bonded to the circuit board 130,the adhesive resin AR may be continuously formed to entirely cover theconnection member 125 together with the bonding portions formed at theone end and the other end of the connection member 125, and accordingly,the connection member 125 may be stably supported without moving by anexternal impact.

The adhesive resin AR may include a two-component curable resinincluding different components. In an implementation, the adhesive resinAR may include an epoxy adhesive, and may include a two-componentcurable resin including epoxy as a main material and amine as a curingagent. In an implementation, the adhesive resin AR may be applied on theconnection member 125 and then cured by heating or curing in a timelymanner, and according to an embodiment, the adhesive resin AR may becured by irradiating UV light. The cured adhesive resin AR may firmlysupport the entire connection member 125, including the one end and theother end thereof. The adhesive resin AR may be applied on theconnection member 125 based on proper fluidity when uncured, forexample, may be injected through the connection hole CH, may be curedby, after injection, irradiating UV light, heating, or curing in atimely manner, and then may firmly support the connection member 125.

Referring to FIGS. 10 and 11 , the adhesive resin AR may cover the edgeportions of the upper end portions 10 a of the adjacent battery cells 10exposed through the connection hole CH. In this case, the connectionhole CH may expose the hollow protrusions 115 connected to the coolingflow paths F formed around the battery cell 10 covered with the adhesiveresin AR. In an implementation, the connection hole CH may expose a pairof hollow protrusions 115 facing each other with the connection members125 therebetween, and in this case, the pair of hollow protrusions 115may be formed between the pair of battery cells 10 exposed through theconnection hole CH.

Throughout the present specification, in the case where the adhesiveresin AR is formed at a position corresponding to the edge portion ofthe upper end portion 10 a or the lower end portion 10 b of the batterycell 10 in the height direction of the battery cell 10, the adhesiveresin AR may be formed on the edge portion of the battery cell 10 tocover the junctions of the connection members 125, and the adhesiveresin AR may be filled in the connection holes CH of the circuit board130 formed on the upper portion of the battery cells 10.

In the present disclosure, in relation to the edge portion of the upperend portion 10 a of the battery cell 10 at which the adhesive resin ARis formed, the adhesive resin AR may be formed at the edge portion ofthe upper end portion 10 a of the battery cell 10 to which theconnection member 125 is coupled. In this case, the edge portion of theupper end portion 10 a of the battery cell 10 refers to a position ofthe upper end portion 10 a of the battery cell 10 to which theconnection member 125 is coupled, and the edge position of the upper endportion 10 a of the battery cell 10 is not limited. In animplementation, in relation to the position where the adhesive resin ARis formed, the edge portion of the upper end portion 10 a of the batterycell 10 may refer to an outer area of the upper end portion 10 a of thebattery cell 10, other than the central portion, that is, an outer areasurrounding the central portion, to distinguish a position where any oneof the first and second electrodes 11 and 12 of the battery cell 10 isformed from a position where another electrode is formed, along theupper end portion 10 a of the battery cell 10, and in relation to theposition where the adhesive resin AR is formed, the edge portion of theupper end portion 10 a of the battery cell 10 may refer to an outer areaof the upper end portion 10 a of the battery cell 10, based on theboundary between the one electrode and another of the battery cell 10.

As described above with reference to FIG. 3 , the second electrode 12 ofthe battery cell 10 may be formed at the central portion of the upperend portion 10 a of the battery cell 10, and the first electrode 11 maybe formed at the edge portion of the upper end portion 10 a and thelower end portion 10 b. In this case, in relation to the position towhich the connection member 125 is coupled, the edge portion of theupper end portion 10 a of the battery cell 10 may refer to the firstelectrode 11 formed at the edge portion of the upper end portion 10 a ofthe battery cell 10.

FIG. 11 illustrates the adhesive resin AR formed on the connectionmembers 125 that connect the upper end portions 10 a of the batterycells 10 to the circuit board 130. In an implementation, the circuitboard 130 may be selectively formed on the upper end portion 10 a of thebattery cell 10 (i.e., the circuit board 130 is selectively arrangedonly on the upper holder 110 a), and according to another embodiment,the circuit board 130 may be formed under the lower end portions 10 b ofthe battery cells 10, and in this case, the adhesive resin AR may beformed on the connection members 125 that connect the lower end portions10 b of the battery cells 10 to the circuit board 130.

The potting resin PR and the adhesive resin AR contribute to differentpurposes, and they may include different components having differentmaterial characteristics. In an implementation, the potting resin PR mayhave a function of protecting the coupling portions of the bus bars 120from harmful elements such as oxygen or moisture, and thus, may haveairtightness to prevent penetration of the harmful elements. In animplementation, the adhesive resin AR may have adhesion to be firmlyattached to the connection members 125 thereby protecting the connectionmember 125 such as a conductive wire or a conductive ribbon from anexternal impact.

Referring to FIGS. 14 to 16 , the separation member 140 may be arrangedon the cell holder 110. The separation member 140 may spatially separatethe cooling flow paths F for the cooling medium CM for cooling thebattery cells 10, from the exhaust gas path for the exhaust gas DGdischarged from the vent portions 13 of the battery cells 10. In animplementation, the separation member 140 spatially separates thecooling flow paths F from the exhaust gas path, thereby removing a riskof explosion or fire due to mixing of the high-temperature andhigh-pressure exhaust gas DG flowing through the exhaust gas path andthe cooling medium CM such as air flowing through the cooling flow pathsF. In an implementation, in the battery pack mounted on an electricvehicle, the exhaust gas (DG) may be prevented from flowing into theinterior of the vehicle along an uncontrolled path.

Referring to FIG. 1 , the separation member 140 may include an upperseparation member 140 a arranged on the upper holder 110 a and a lowerseparation member 140 b arranged under the lower holder 110 b. In animplementation, the upper separation member 140 a may be arranged on thecircuit board 130 arranged on the upper holder 110 a. In animplementation, the circuit board 130 may not be arranged under thelower holder 110 b, and thus the lower separation member 140 b may bearranged directly under the lower holder 110 b. For example, the lowerseparation member 140 b may be arranged under the lower bus barsarranged under the lower holder 110 b.

Referring to FIG. 14 , open regions 145 through which the cooling flowpaths F passes may be formed in the separation member 140. The coolingflow path F may be formed across the separation member 140 while passingthrough the open region 145 of the separation member 140, e.g., thehollow protrusion 115 of the cell holder 110 may be inserted into theopen region 145 of the separation member 140, and thus the cooling flowpath F that passes through the open region 145 of the separation member140 may be formed. To this end, the open regions 145 of the separationmember 140 may be formed at positions corresponding to the hollowprotrusions 115 and may be formed in a shape corresponding to the hollowprotrusions 115. In an implementation, the open region 145 may be formedin a circular shape corresponding to the hollow protrusion 115 includingthe circular wall body 115 a that surrounds the central hollow portion.In an implementation, the open region 145 may be formed in variousshapes corresponding to the hollow protrusion 115, for example, anelliptical shape or various polygonal shapes including a hexagon.

Referring to FIG. 15 , according to an embodiment, the open region 145may include a wall body 145 a that extends toward the hollow protrusion115, and the wall body 115 a of the hollow protrusion 115 may beinserted into the wall body 145 a of the open region 145. In this case,the wall body 145 a of the open region 145 and the wall body 115 a ofthe hollow protrusion 115 may be formed in circular shapes correspondingto each other at positions corresponding to each other, and may beassembled by being press-fit toward each other. In an implementation,the outer circumference of the wall body 115 a of the hollow protrusion115 may be inserted into the inner circumference of the wall body 145 ain the open region 145, and the wall body 115 a of the hollow protrusion115 and the wall body 145 a in the open region 145 may be assembled bybeing press-fit toward each other. In an implementation, the wall body145 a of the open region 145 may have an inner circumference having asize that decreases gradually toward the hollow protrusion 115, or thewall body 115 a of the hollow protrusion 115 may have an outercircumference having a size that increases gradually toward the openregion 145, and the wall body 145 a of the open region 145 or the wallbody 115 a of the hollow protrusion 115 may have a gradient along thedirection of protruding toward each other such that the wall body 145 aof the open region 145 and the wall body 115 a of the hollow protrusion115 may be press-fit toward each other.

The separation member 140 may include spacers 141 that protrude towardthe cell holder 110 to maintain a predefined gap between the separationmember 140 and the cell holder 110. The gap between the separationmember 140 and the cell holder 110, which is maintained by the spacers141, may provide the exhaust gas path for the exhaust gas dischargedfrom the battery cells 10. As will be described below, a space betweenthe blocking region 144 of the separation member 140 and the cell holder110 may form the exhaust gas path through which the exhaust gasdischarged from the upper end portions 10 a of the battery cells 10 orthe lower end portions 10 b of the battery cells 10 (e.g., the ventportions 13 formed at the upper end portions 10 a or the lower endportion 10 b of the battery cells 10) is discharged, and in this case,the spacers 141 of the separation member 140 may maintain an appropriategap between the separation member 140 and the cell holder 110. In animplementation, the spacers 141 formed at the upper separation member140 a may provide the exhaust gas path for the exhaust gas dischargedfrom the upper end portions 10 a of the battery cells 10 whilemaintaining the gap between the upper side of the upper holder 110 a andthe blocking region 144 of the upper separation member 140 a, and thespacers 141 formed at the lower separation member 140 b may provide theexhaust gas path for the exhaust gas discharged from the lower endportions 10 b of the battery cells 10 while maintaining the gap betweenthe lower side of the lower holder 110 b and the blocking region 144 ofthe lower separation member 140 b.

Referring to FIGS. 14 and 15 , the open regions 145 of the upper andlower separation members 140 a and 140 b may be formed at positionscorresponding to each other to form the cooling flow paths F that passthrough at least a portion of the battery pack. The open regions 145 ofthe upper and lower separation members 140 a and 140 b may form thecooling flow paths F that pass through substantially the entirestructure of the battery pack, together with the hollow protrusions 115of the cell holder 110 interposed between the upper and lower separationmembers 140 a and 140 b, and the open regions 135 of the circuit board130 interposed between the upper and lower separation members 140 a and140 b. In an implementation, the cooling flow path F may connected fromthe upper separation member 140 a, through the circuit board 130, theupper and lower holders 110 a and 110 b, between the battery cells 10inserted into the upper and lower holders 110 a and 110 b, and to thelower separation member 140 b, to pass through substantially the entirestructure of the battery pack in the height direction. To this end, theopen regions 145 of the upper and lower separation members 140 a and 140b and the open regions 135 of the circuit board 130 may be formed atpositions corresponding to each other, and may be formed at positionscorresponding to the hollow protrusions 115 such that the hollowprotrusions 115 of the cell holder 110 may be inserted into the openregions 145 and the open regions 135.

The separation member 140 may include the blocking region 144 formed ata position corresponding to the vent portions 13 of the battery cell 10.Hereinafter, the blocking region 144 formed at the upper separationmember 140 a will be mainly described. However, the technical aspects ofthe upper separation member 140 a described below may be substantiallyequally applied to the lower separation member 140 b.

Referring to FIG. 16 , the blocking region 144 may be formed to blockareas above the vent portions 13 such that the exhaust gas DG dischargedfrom the vent portions 13 (or the terminal holes 112 exposing the ventportions 13) of the battery cells 10 may not pass through the separationmember 140. For example, the blocking region 144 may be formed in aclosed shape, and unlike the open regions 145, the separation member 140may not have an opened portion such that the upper and lower sides ofthe separating member 140 are not fluidly connected to each other, andthe upper and lower sides of the separation member 140 are separatedfrom each other, and thus the lower side of the blocking region 144 inwhich the vent portions 13 (or the terminal holes 112 exposing the ventportions 13) are arranged and the upper side of the blocking area 144may not be fluidly connected to each other.

As described above, the lower side of the blocking region 144 in whichthe vent portions 13 (or the terminal holes 112 exposing the ventportions 13) may be arranged and the upper side of the blocking area 144may not be fluidly connected to each other and may be separated fromeach other, thus the exhaust gas DG discharged from the vent portions 13(or the terminal holes 112 exposing the vent portions 13) may not passthrough the blocking region 144 and may not be discharged to an upperportion of the blocking region 144, and the exhaust gas DG dischargedfrom the vent portions 13 (or the terminal holes 112 exposing the ventportions 13) may be blocked by the blocking region 144 to flow along theexhaust gas path between the blocking region 144 and the battery cells10, and may be discharged to the outside of the battery pack along theexhaust gas path.

Referring to FIG. 7 , according to an embodiment, the group of thebattery cells 10 that constitutes the battery pack may be arranged inwhich one of the pair of adjacent battery cells 10 is inverted in theheight direction, and may include the first group of the battery cells10 in which the vent portions 13 are formed at the upper end portions 10a and the second group of battery cells 10 in which the vent portions 13are formed in the lower end portions 10 b. In this case, as illustratedin FIG. 16 , the blocking region 144 of the upper separation member 140a arranged on the upper side of the upper holder 110 a may be formed ina closed shape such that one side of the upper separation member 140 a,in which the upper end portions 10 a (or the vent portions 13) of thefirst group of the battery cells 10 are arranged, and the other side ofthe upper separation member 140 a, which is opposite to the upper endportions 10 a (or the vent portions 13) of the first group of thebattery cells 10, are not fluidly connected to each other. Similarly,the blocking region 144 of the lower separation member 140 b arrangedunder the lower side of the lower holder 110 b may be formed in a closedshape such that one side of the lower separation member 140 b, in whichthe lower end portions 10 b (or the vent portions 13) of the secondgroup of the battery cells 10 are arranged, and the other side of thelower separation member 140 b, which is opposite to the lower endportions 10 b (or the vent portions 13) of the second group of thebattery cells 10, are not fluidly connected to each other.

Referring to FIG. 16 , the blocking region 144 is not limited topositions corresponding to the vent portions 13 (or the terminal holes112 exposing the vent portions 13) of the battery cells 10, and may beformed over the entire area of the separation member 140 other than theopen regions 145. For example, the blocking region 144 may extend to theentire area of the separation member 140, other than the open regions145 for penetration of the cooling flow paths F, between the openregions 145, and may form the exhaust gas path continuously connectedfrom positions corresponding to the vent portions 13 (or the terminalholes 112 exposing the vent portions 13) to the exhaust hole DH. Forexample, the exhaust gas DG discharged from the vent portions 13 (or theterminal holes 112 exposing the vent portions 13) at different positionsmay be collected into the exhaust hole DH along the exhaust gas pathcontinuously formed between the blocking region 144 of the separationmember 140 and the battery cells 10. According to an embodiment, theexhaust gas path may be formed between the blocking region 144 of theseparation member 140 and the battery cells 10 or between the blockingregion 144 of the separation member 140 and the cell holder 110 (or thecircuit board 130), and may be continuously formed from the vent portion13 (or the terminal hole 112 exposing the vent portion 13) of eachbattery cell 10 to the exhaust hole DH formed at one side of the cellholder 110. In an implementation, the exhaust gas path may be formed ina manner in which spaces between the hollow protrusions 115 insertedinto the open regions 145 of the separation member 140 are continuouslyconnected to each other, and the exhaust gas DG collected into theexhaust hole DH through the exhaust gas path may be discharged to theoutside of the battery pack. According to an embodiment, the exhaust gaspath for the exhaust gas discharged from the upper end portions 10 a orthe lower end portions 10 b (or the vent portions 13 formed at the upperend portions 10 a or the lower end portions 10 b) of the battery cells10 may be formed between the upper side of the upper holder 110 a andthe upper separation member 140 a and between the lower side of thelower holder 110 b and the lower separation member 140 b, and may beformed in a manner in which spaces between the hollow protrusions 115inserted into the open regions 145 of the upper separation member 140 aand the lower separation member 140 b are continuously connected to eachother.

The exhaust gas path, one side of which is closed by the blocking region144 formed in a closed shape such that the upper and lower sides of theseparation member 140 are not connected to each other, may be spatiallyseparated from the cooling flow paths F passing through the upper andlower sides of the separation member 140 through the open regions 145 ofthe separation member 140. More specifically, the separation member 140may be formed generally in a plate shape having a closed shape, exceptfor the open regions 145 into which the hollow protrusions 115 areinserted. In this case, the cooling flow paths F may pass through theseparation member 140 through the open regions 145 while beingsurrounded by the hollow protrusions 115, and may be spatially separatedfrom the exhaust gas path formed between the separation member 140 (theblocking region 144) and the battery cells 10, and by the structure inwhich the cooling flow paths F and the exhaust gas path are spatiallyseparated from each other, a risk of a safety accident that may causeexplosion or ignition due to mixing of the cooling medium CM flowingalong the cooling flow path F and the high-temperature and high-pressureexhaust gas DG flowing along the exhaust gas path, may be reduced, andin the case of the battery pack mounted on an electric vehicle, theexhaust gas DG may be prevented from being introduced into the interiorof the vehicle through the separation member 140, and thus the safety ofpassengers from toxic gas may be secured.

Referring to FIGS. 1 and 17 , an upper duct 150 a and a lower duct 150 bmay be arranged on the upper separation member 140 a and under the lowerseparation member 140 b, respectively. An opening OP through which thecooling medium is introduced, may be formed at the upper duct 150 a, andthe cooling medium introduced into the battery pack through the openingOP may cool the battery cells 10 while passing through the cooling flowpaths F formed from the upper separation member 140 a to the lowerseparation member 140 b. The cooling flow paths F may be formed betweenthe adjacent battery cells 10, and the battery cells 10 may be cooled bythe cooling medium vertically flowing in the height direction of thebattery cells 10.

The lower duct 150 b may be connected to a fluid device for generating apressure difference between the inside and the outside of the batterypack, to force a flow of the cooling medium passing through the batterypack. For example, a connection portion M for the fluid device may beformed at one side of the lower duct 150 b. In an implementation, thefluid device may be a suction type pump for maintaining an internalpressure of the battery pack to be a negative pressure with respect tothe external atmosphere of the battery pack. The fluid device (or theconnection portion M for the fluid device) connected to the lower duct150 b may form an outlet of the cooling medium introduced through theopening OP of the upper duct 150 a. In an implementation, the opening OPof the upper duct 150 a may form the inlet of the cooling medium, andthe fluid device (or the connection portion M for the fluid device)connected to the lower duct 150 b may form the outlet of the coolingmedium. In an implementation, the fluid device may be a blower typepump, and in this case, the fluid device (or the connection portion Mfor the fluid device) connected to the lower duct 150 b may form theinlet of the cooling medium, and the opening OP of the upper duct 150 amay form the outlet of the cooling medium.

A negative pressure may be generated in the battery pack by operation ofthe fluid device, the cooling medium may be introduced into the batterypack through the opening OP of the upper duct 150 a by a pressuredifference between the inside and the outside of the battery pack, andthe cooling medium introduced into the battery pack may cool the batterycells 10 while passing through the cooling flow paths F and may bedischarged to the outside of the battery pack through the fluid deviceconnected to the connection portion M of the lower duct 150 b.

In an implementation, the opening OP formed in the upper duct 150 a andthe fluid device (or the connection portion M for the fluid deviceformed in the lower duct 150 b) connected to the lower duct 150 b mayform the inlet and the outlet of the cooling medium, respectively, andthus, the position of the opening OP formed in the upper duct 150 a andthe position (or the position of the connection portion M formed in thelower duct 150 b) of the fluid device connected to the lower duct 150 bmay be indicated on both ends of a diagonal line crossing the batterypack in an diagonal direction.

In relation to the positions of the inlet and the outlet of the coolingmedium, the diagonal direction of the battery pack may refer to adirection that simultaneously follows the height direction of thebattery cell 10 and the direction Z1 of the long side lines of theenvelope S1 and S2 (see FIG. 4 ) surrounding the battery cells 10. Thatis, supposing that the group of battery cells 10 that constitutes thebattery pack is surrounded by the rectangular envelope S1 and S2 (seeFIG. 4 ) consisting of the pair of long side lines S1 and the pair ofshort side lines S2 that extend to linearly surround the circumferenceof the group of battery cells 10, the diagonal direction of the batterypack may refer to the direction that simultaneously follows the heightdirection of the battery cell 10 and the direction Z1 of the long sidelines of the envelope S1 and S2. For reference, the direction Z1 of thelong side lines and the direction Z2 of the short side lines of theenvelope S1 and S2 may correspond to the direction of long side linesand the direction of the short side lines of the cell holder 110,respectively, and may correspond to the direction of long side lines andthe direction of the short side lines of the battery pack, respectively.

In an implementation, the flow of the cooling medium passing through theinside of the battery pack may be induced by using the opening OP of theupper duct 150 a and the fluid device of the lower duct 150 b (or theconnection portion M formed in the lower duct 150 b) formed at both endsof the diagonal line crossing the battery pack in the diagonaldirection. In an implementation, the position of the opening OP formedin the upper duct 150 a and the position of the fluid device (or theconnection portion M formed in the lower duct 150 b) connected to thelower duct 150 b may be formed at positions spaced apart from each otheralong the direction Z1 of the long side lines of the envelope S1 and S2or the direction Z1 of the long side lines of the battery pack, and forexample, in the case where the position of the opening OP formed in theupper duct 150 a, e.g., the position of at least a portion of theopening OP formed in the upper duct 150 a is formed at one edge positionalong the direction of the long side lines of the battery pack, theposition of the fluid device connected to the lower duct 150 b (or theposition of the connection portion M formed in the lower duct 150 b) maybe formed at the other edge position along the direction of the longside lines of the battery pack. As described above, the opening OPformed in the upper duct 150 a and the fluid device (or the connectionportion M formed in the lower duct 150 b) connected to the lower duct150 b may be formed at the one edge position and the other edge positionalong the direction of the long side lines of the battery pack, andaccordingly, the flow of the cooling medium that connects the opening OPof the upper duct 150 a to the fluid device (or the connection portion Mformed in the lower duct 150 b) of the lower duct 150 b may be formed tocross the inside of the entire battery pack.

As described above, the connection portion M for the fluid device may beformed at the one edge portion of the battery pack in the direction ofthe long side lines of the battery pack, and a fixing portion FX for thefluid device may be formed together with the connection portion M forthe fluid device at the one edge portion of the battery pack in whichthe connection portion M for the fluid device is formed. That is, aninlet or an air blowing hole of the fluid device, according to a type ofthe fluid device, may be connected to the connection portion M for thefluid device, and the position of the fluid device may be fixed by thefixing portion FX for the fluid device. The exhaust pipe DP may beformed at the one edge portion of the battery pack in which theconnection portion M for the fluid device is formed. Since the exhaustpipe DP requires an installation space to protrude toward the outside ofthe battery pack, the exhaust pipe DP may be formed at one edge portionof the battery pack to which the fluid device is connected, and theconnection portion M for the fluid device, the fixing portion FX for thefluid device, and the exhaust pipe DP may be formed at one edge portionof the battery pack, and accordingly, the other edge portion of thebattery pack may provide a position alignment surface of the batterypack, for example, a reference surface for position alignment with anelectric vehicle on which the battery pack is mounted.

One or more embodiments may provide a battery pack which is advantageousfor slimming, in that the length of a connection member that forms avoltage measurement line between a circuit board and a battery cell maybe reduced by decreasing the distance between the battery cells and thecircuit board, the connection members may be firmly bonded, and theamount of potting resin injected through filling holes of the circuitboard may be reduced.

Example embodiments have been disclosed herein, and although specificterms are employed, they are used and are to be interpreted in a genericand descriptive sense only and not for purpose of limitation. In someinstances, as would be apparent to one of ordinary skill in the art asof the filing of the present application, features, characteristics,and/or elements described in connection with a particular embodiment maybe used singly or in combination with features, characteristics, and/orelements described in connection with other embodiments unless otherwisespecifically indicated. Accordingly, it will be understood by those ofskill in the art that various changes in form and details may be madewithout departing from the spirit and scope of the present invention asset forth in the following claims.

What is claimed is:
 1. A battery pack, comprising: a plurality of battery cells; a plurality of bus bars, each bus bar: electrically connecting two different battery cells among the plurality of battery cells, and including coupling pieces at opposite ends thereof that are coupled to the two different battery cells, and a protruding connecting piece at a center of the bus bar that connects the coupling pieces at opposite ends; a circuit board on the plurality of bus bars and electrically connected to at least a portion of the plurality of battery cells, the circuit board having escape holes that expose the protruding connecting piece of each bus bar; and a cell holder, the cell holder having: a first side in which the battery cells are accommodated, and a second side including hollow protrusions connected to cooling flow paths between adjacent battery cells of the plurality of battery cells, wherein the circuit board further includes a bus opening region continuous with the escape holes in a single hole shape, the bus opening region exposing the hollow protrusions of the cell holder and the protruding connecting pieces of the plurality of bus bars.
 2. The battery pack as claimed in claim 1, wherein each escape hole completely exposes a corresponding protruding connecting piece.
 3. The battery pack as claimed in claim 1, wherein the protruding connecting pieces do not overlap a solid portion of the circuit board that surrounds the escape holes.
 4. The battery pack as claimed in claim 1, wherein each escape hole completely accommodates a corresponding protruding connecting piece.
 5. The battery pack as claimed in claim 1, wherein: the circuit board has a lower side facing the plurality of battery cells and an upper side that is opposite to the plurality of battery cells, along a height direction of the plurality of battery cells, and a plane of each protruding connecting piece is between a plane of the upper side of the circuit board and a plane of the lower side of the circuit board.
 6. The battery pack as claimed in claim 1, wherein the bus bars and the circuit board are on the second side of the cell holder.
 7. The battery pack as claimed in claim 1, wherein each bus bar extends between a corresponding pair of the hollow protrusions that face each other.
 8. The battery pack as claimed in claim 7, wherein the pair of the hollow protrusions face each other in a direction intersecting a lengthwise extending direction of the bus bar therebetween.
 9. The battery pack as claimed in claim 7, wherein the protruding connecting piece of each bus bar is between the corresponding pair of the hollow protrusions.
 10. The battery pack as claimed in claim 9, wherein the cell holder further includes pairs of locking steps, into which the protruding connecting piece of each bus bar is inserted, at each of the pairs of hollow protrusions, the pairs of locking steps each protruding from wall bodies of the corresponding pair of hollow protrusions toward the protruding connecting piece therebetween.
 11. The battery pack as claimed in claim 10 wherein the cell holder further includes mold holes from which the pairs of hollow protrusions protrude, at positions corresponding to the pairs of locking steps, to pass through the cell holder.
 12. The battery pack as claimed in claim 7, wherein: each bus bar further includes position alignment holes for position alignment with the cell holder, the position alignment holes being in the protruding connecting piece of each bus bar, and the cell holder further includes position alignment pins that are insertable into the position alignment holes of corresponding bus bars, the position alignment pins being between the pairs of hollow protrusions.
 13. The battery pack as claimed in claim 12, wherein pairs of the position alignment pins are arranged along a lengthwise direction of a corresponding one of the plurality of bus bars.
 14. The battery pack as claimed in claim 1, wherein the bus opening region exposes pairs of the hollow protrusions together with the protruding connecting pieces therebetween.
 15. The battery pack as claimed in claim 1, further comprising connection members on the circuit board, passing through the circuit board, and connected to the battery cells, wherein: the circuit board further includes connection opening regions, the connection members pass through the connection opening regions of the circuit board, and the connection opening regions expose pairs of the hollow protrusions facing each other with corresponding connection members therebetween.
 16. The battery pack as claimed in claim 15, wherein respective ends of the connection members are ultrasonically welded to the circuit board and the battery cell.
 17. The battery pack as claimed in claim 15, wherein the bus opening region and the connection opening region are continuous with each other to form a second opening region in a single hole shape.
 18. The battery pack as claimed in claim 17, wherein the second opening region exposes: a first hollow protrusion of the hollow protrusions that is between a first bus bar of the plurality of bus bars and a first connection member of the connection members, a second hollow protrusion of the hollow protrusions that faces the first hollow protrusion with the first bus bar therebetween, and a third hollow protrusion of the hollow protrusions that faces the first hollow protrusion with the first connection member of the connection members therebetween. 